what a lot of people forget/look-over is that 'LiPos' inherently by construction already have a weight bias/offset unlike NiCd and NiMh. Put any LiPo on the table, draw a line across the middle, 'pick up' that LiPo on the line to check its natural balance. Bullet Plug Terminal side will be light. Its actually difficult to balance a chassis left-to-right with a shorty in my experience..
I think this layout is superb, without knowing the details... bravo!!