I'm with the others, chest rigs aren't really suited to the sniper role in airsoft.
Neither are belt/drop leg holsters.
I am experimenting with a couple of different solutions for my sniper kit, and I found out that the chest rig I was wearing (TT mini mav, thing's TINY) was getting in the way of my armpit holster and vice versa, especially with the pistol holstered.
Thing is, chest rigs are good for drawing stuff like magazines when prone, as you don't have to move a lot to reach that pouch on your hip.
But then, depending on the size and how you fit it, it can prevent you from comfortably laying down, whereas a belt doesn't really get in the way of anything.
Belt mounted holsters are cool and all, but try laying on your side to aim at that unexpected guy who shows up next to you. Now try to do it with a dtd holster.
Armpit holster is the way to go, you can draw from any stance your body allows and it doesn't give your position away (remember, the first thing the human eye notices is movement).
Get (or craft) a decent armpit holster and carry everything else on a belt.