If you look at what many people call a "Weaver Stance," it often bears little resemblance to the actual stance Jack Weaver used during the Leatherslap Competitions, and what he described and demonstrated in later times. Many modern shooters drop into a much deeper stance than he typically did, blading their bodies more. Weaver's right foot would often be back only slightly, and he dropped his head and tilted it slightly to align with the sights. His posture was often almost straight upright. Weaver was looking more to get quick, accurate single shots for competition, believing it was better to hit a little slower than to miss fast. Even then, he wasn't really slower.
As for my personal stance, I can only say "it varies." I'll try not to be too confusing as I write this. I shoot rifles and shotguns right handed, and I am right eye dominant, despite being left handed. I shoot revolvers for Cowboy Action "Double Duelist" style, shooting first one with one hand, then the other with the opposite hand. Otherwise, I will shoot pistols with a two handed grip most of the time, unless I am training for something specific. Prior to taking up Cowboy Action, I shot trap competitively for years, beginning in college about the same time I was shooting rifles in the Army. I became involved in Kenpo while shooting trap, all of which means it feels natural for me to drop my right foot back into what would typically be a Kenpo Fighting Stance. This is true for all types of firearms. The exception being when shooting for Cowboy Action, where I will square up for revolvers, since I am shooting one handed, with both hands.
When the Army began training toward the isosceles stance with pistols, to keep ballistic plates toward the threat as others have mentioned, I worked hard to shift my training in that regard with pistol and with the M4 Carbine. I still tend to drop my right foot back, although I keep my body fairly square. I also tend to put my weight forward somewhat and bend my knees. The big difference for me, is that where Jack Weaver relied on an isometric "push-pull" grip, I definitely follow the isosceles method in pushing out from the chest and allowing that to cause my grip to tighten on the firearm. This is true even though I will still leave my arms bent slightly at the elbow.
