Regarding Residual Metamagic, Twin Spell and Repeat Spell. (SCM)

[Kasz]

So, when I'm a little higher level I'll hopefully have all the required feats for this... but just trying to work out how this interacts with eachother.

As a Shadowcraft mage.

I cast Planar Bubble, combined with umbral necklace to basically create a bubble of the shadow plane. This Maximises my shadow spells for free.

I Heighten a silent image from a cantrip (gnome illusionist) to occupy a 9th level slot, thanks to earth spell shenanigans it counts as a 10th level spell.

I convert the silent image (shadow illusion) into a shadow evocation, this is a 10th level spell in a 9th level slot, so I can emulate... Meteor Swarm for example.

I cast Meteor Swarm at 160% quasi-reality (My DM has ruled that we skip the save once I reach 100%+ as it's beneficial for me, makes the most sense, and less confusing) and it's maximised. So it deals it's damage and reflex saves are made.

Question 1. The Reflex saves are keyed off my illusion spell DCs even though it's a shadow evocation, correct?

Next round, I use residual magic and cast the cantrip silent image heightened up to 10th level but occupying a cantrip slot. I also decide to add Twin Spell and Repeat Spell. Which puts me up to a 7th level slot. I use Shadow Illusion to make the silent image into a "Crushing Hand" evocation, I cast two big hands of shadow due to twin, they do their thing.

Next Round Repeat spell kicks in.... now here is my confusion. Does it:
A) Repeat Spell cast a silent image but in a 3rd level slot, So I could emulate a 3rd level spell
B) Repeat Spell cast a silent image but in a 3rd level slot, but with the heighten, so I could emulate a 9th level spell.
C) Repeat Spell cast a silent image but in a 7th level slot because it includes Twin Spell, So I could emulate a 7th level spell
D) Repeat Spell cast a silent image but in a 7th level slot because it includes Twin Spell, but including the free heighten, So I could emulate a 9th level spell.
E) Repeat Spell the Twinned Crushing Hands, but in a 3rd level slot.
F) Repeat Spell the Crushing Hand spell, but in a 3rd level slot.
G) Other!?!

Also I have my actions as repeat spell doesn't take up my turn, So I just move away and cast a heightened silent image to replicate a Haboob on top of my grappled foes.

[Unbeliever]

I've been considering this stuff as well.  But ...

Next round, I use residual magic and cast the cantrip silent image heightened up to 10th level but occupying a cantrip slot. I also decide to add Twin Spell and Repeat Spell. Which puts me up to a 7th level slot. I use Shadow Illusion to make the silent image into a "Crushing Hand" evocation, I cast two big hands of shadow due to twin, they do their thing.

I don't think you can do this.  You use Residual Magic next round to cast your cantrip with the awesome Heighten for free.  I'm not sure you can layer additional metamagic feats onto that.  That would turn it into like a 14th level spell or something, which you can't cast barring a whole lot of epic feats.  So, I think you're just stuck, sadly [sarcasm] with casting high level spells on the cheap.  But, you can't layer any additional metamagic feats onto them.

As a side note, that privileges high level spells rather than metamagicked ones for this type of build.  Though a forgiving DM, like me, would let you research some custom spells to work around that .

[Kasz]

Residual Metamagic
Lingering Metamagic: If you cast a spell affected by one or more metamagic feats, and then cast the same spell in the next round, you can apply any one of the metamagic effects from the first casting to the second casting, but without any change to the spell's level. The second spell doesn't count as being affected by a metamagic feat for the purpose of this benefit (that is, it doesn't entitle you to apply the metamagic feat to a spell you might cast in the following round). Only spells you cast using your own metamagic feats (as opposed to metamagic effects from magic items) allow this option to function. For example, if Hennet uses a 5th-level slot to cast an empowered lightning bolt, in the next round he can use a 3rdlevel slot to cast another empowered lightning bolt. If the first spell was a silent empowered lightning bolt, he could apply the effect of either Silent Spell or Empower Spell to the second casting of lightning bolt, but not both.

The feat states you can only apply one metamagic feat for free, it also suggests you cannot further increase it with metamagic. So I agree with you Unbeliever. Although it isn't completely clear as it doesn't state you can't use additional metamagic on this spell normally, just "you can only apply one of your feats for free".

I suppose maybe my question should just be... how does repeat spell work with silent image, when you're using it to cast shadow conjurations or evocations. I guess I should just treat it like casting Shades.

[Unbeliever]

Actually, looking at the quote I am less sure than I was before. 

Take the Hennet example.  In round 2, could he then apply Silent Spell to the second casting of Lightning Bolt, using a 4th level slot?  It's completely unclear.  In the absence of there being any mention of restriction, I'm inclined to allow it, perhaps on a general rule of not being unduly restrictive with regards to metamagic feats.  You could just have easily cast a 4th level spell, and the theory is that a 3rd level spell +1 level of metamagic is roughly equivalent, maybe even a little better b/c of the feat commitment. 

I've also thought more about the spell level problem:  you're usually not allowed to cast 14th level spells or what have you.  But, then again, there's no general restriction on that with other metamagic reducers -- it's always spelled out.  There's no reason, for instance, that you can't use DMM(persist) on a 9th level spell. 

[Kasz]

a. So how does a twinned repeating scorching ray resolve?

b. How does a twinned repeating shadow evocation resolve?

c. How does Twinned Work with Shadow Evocation?

My best guess.

A.
Scorching Ray (2nd) Twinned (+4) Repeating (+3) = 9th level spell.

First Round
Twinned Repeating Scorching Ray (9th)

Second Round
Twinned Scorching Ray (free) on the same targets.

B.
Shadow evocation (through silent image heightened to a 2nd level spell slot) + Twin + Repeat

First Round
Twinned Repeated Shadow Evocation (9th) -> Illusory Twinned Scorching Ray.

Second Round
Twinned Shadow Evocation (free) -> Illusory Twinned Shatter.

C.
If Twinned just duplicates the spell and the spell is Shadow Evocation, does that mean I can cast two different evocation spells? Because each Shadow Evocation is technically separate, I can resolve them separately?

Allowing a Twinned Shadow Evocation (9th) to be cast as:

Shout
Wall of Ice

(not very powerful but with SCM stuff added it could be)

Assumptions.

1. Repeat Spell says it is cast again. So it repeats my "Twinned Shadow Evocation".
2. Twin Casts ShadowEvocation, not the illusory duplicate of the spell.

My head hurts.

Personally...I think the repeat spell shadow evocations should be limited to the same spell, but reading repeat spell, it just talks about how the targets / duration / area and origin point are the same. Now... Shadow Evocation doesn't have a target... it doesn't have a duration, it doesn't have an area... it just lets you create an illusion.

[Unbeliever]

I would say it's the same spell, too.  So, Twinned Shadow Evocation (Scorching Ray) = 2 sets of Scorching Rays.

This is an extrapolation from the same targets, etc. language in Twin Spell.  If Repeat Spell has similar language, then the same applies.  That might be slightly restrictive, but we're talking about some fairly awesome stuff here and let's not go too far "off book." 

Although, if the spell inherently has some sort of options, like Summon Monster, I'd let you summon 2 different types of monster with Twinned Shadow Conjuration (or the SCM equivalent). 

[Kasz]

So Twinned Summon Monster, you could get 2 different monsters?

Twinned Shadow Conjuration, Summon Monster, you could get 2 different monsters.

It's an interesting interaction of metamagics and spells.