I will answer in reverse chronological order.
I've also been looking into and am working on some custom dice creation.
The tl;dr of that is search for dice at sites like thingiverse and hit up your local college or STEM school. Heck, if you're in the northern area of the states and it's not perverted even the Boy Scouts can hook you up and print something for you.
3D printing is nowhere near what I want. I want something that looks professionally made, something that I could have gotten from Chessex or Q Workshop (but at way cheaper than their custom dice prices). This is just one of the many points we'll have to disagree on. Anyways, I'm getting custom d8s at an affordable price, we're currently fine tuning the design and it's a one man shop so things are slow.
there are a couple good miniature making videos on youtubes, seems like a lot of work per item.
I'm never going to do this. Never ever ever. Please don't try to make me.
I've always wanted to get into miniatures, but never really figured out a way to do so without an enormous buy in. I can't say I have any experience in the field, but I'm always interested in learning new things. I'd assume trays is where I'd need to start, so I'm imagining it would be helpful
Honestly I only got into miniatures because of a Reaper kickstarter. I'm doing custom trays because I'm just not happy with the size/pricing of any of the tray manufacturers or DIY guides that I can find.
So that's one vote of yes for trays (and if I'm doing trays I'll just do all of it in a single thread), and two votes for not caring one way or another.