Fully wound High Cap Questions?

Hey guys,
So I'm getting a crossdraw vest, and I can only hold 3 mags.
A 400 round Hicap, and two others.
My M4, (Echo 1 Stag 15-A4) has a FAST ROF.
And Believe it or not, 400 rounds run pretty fast.
So because I can only hold 3 M4 mags, I was thinking two High caps and a mid cap.
But A problem for me with high caps is that, Their loud, and you have to wind them.

My question is, is there any M4 High caps that would fit into my echo 1 stag-15, and that would also feed all rounds if FULLY wound?
If not, do you think instead of another high cap, that I should just get two mid caps that hold 130 each?

you could always get a leg rig too and attach some extra mag pouches as well so you don't have to even bother with the high caps