I can't keep up with what the different stances are called. I know what Weaver Stance is (strong arm locked out, weak elbow sharply bent strong leg back, weight forward) and I know what Isoceles Stance is (feet square, both elbows locked) but I always get varying explanations for what "Modified Isoceles" is.
Personally, I never even worry about my feet. Left foot forward, right forward, whatever. My upper body turns at the waist to keep the upper body square to the target. For action shooting, this means that I can pay less attention to my feet and concentrate more on shooting sooner when I get to a new position.
I try to keep my shoulders back rather than hunched up around my ears. Both of my elbows are bent, but my weak elbow is less bent than the strong elbow. They're bent at about a 20 degree angle regularly.
Being able to shoot with the elbows bent means that I have a great deal of flexibility in where I can point the gun without making changes to my upper body position, although I still mostly change my aim by rotating my upper body at the waist. Keeping my left arm a bit more rigid means that I can control most of the recoil and guide the firearm with my weak hand, and relax the strong hand for better trigger control.
Like many people, I've gone through the whole range of shooting positions to find what works for me. I have pictures of me shooting Weaver Stance in the early days, but I quickly gave that up for Isoceles, which I shot for a number of years.
You'll find out what works best for you once you've launched a couple hundred thousand rounds downrange.
