Muscle Symmetry's Relation to Posture/Stance

So I have always had a slightly duck-footed resting stance, mostly while sitting. It is fairly unnoticable while walking, however if I try to focus on keeping my feet entirely parallel while sitting it feels unnatural. Up until beginning my bulk I hardly noticed it, however now that I have tossed on some more weight the extent of my stance has become more bothersome. My question is whether or not a hamstring/quadricep dominance could be causing the issues with a comfortable resting stance. Just from looking at my numbers my hamstring work is progressing at a higher rate than my quadriceps, but this could also just be the simple push/pull difference. In relation to posture I have noticed that since beginning my bulk my shoulders tend to roll forward less. Having broke my back in '07 (T11/12) I have always had the tendancy to slump forward, I have noticed an improvement in this area.

Anyway, do you all have any input?