Pretty straight forward question by a pretty unknowing person. I haven't played a ranged character that wasn't a mage in so many years; and that was before I figured out optimizing crap
So, all I really know are the Rapid shot feat tree (cause Many Shot will be useless as I'll be going for a Sniper-esque type archer) and the Splitting weapon enhancement.
The character will be level 16, gestalt, and both on Pathfinder feat progression (a feat every odd level) and have 2 flaws for 2 feats so plenty of room in that regard.
I also kind of wanted to wedge in the Hawkguard ACF (ranged combat ACF) for Warder from Path of War and finagle some of that ranged martial school I can't remember the name of from the same book.
Potentially also hide a bit of Bard within because DFI sounds, at least to me, wonderful on a Volley Archer and I've been loving the idea of having a Bow that is also a Harp.
Also to satisfy the Sniping part of all this (because it doesn't feel very Sniper-ey(?) to be firing an entire volley and darkening the sky with countless arrows) I was looking at wrapping it up with Clustered Shots (which also helps with a DR problem).
How do I get more attacks?
(I have looked at that Archery Handbook and its Volley Archer section, but that doesn't help me make choices and I'm having a hard time making choices because I can't see what it'll look like in the end with even some sort of example >.> )