I'd say 90-95% of my handgun shooting would be a modified Weaver or "speed Chapman".
For 2-handed shooting? Me too, depending. Depends on body positioning for the circumstances, whether a type of barricade/cover is involved and whether/how I have to be able to move (either between or during shots).
For example, going up & down stairs, while remaining balanced and preparing for different elevations of a potential threat, can be more interesting than some folks might think. Clearing corners of potential obstructions ... corners, door jambs, car doors/window frames, furniture, etc ... can also introduce some potential nasty surprises. Even just stepping up and over, or back & over/down, over curbs can become problematic.
Training & qual courses-of-fire which still require 1-handed shooting are also exceptions, of course.
My thoughts on "stances" have been heavily influenced by my martial arts involvement. What's done for learning and skills development is one thing. What's needed for dynamic, fast-paced, stressful and unpredictable situations in the real world may require some flexibility and the ability to transition among balanced
learned positioning and postures. Quickly, at times.
I try to work with folks to emphasize their ability to form a "master grip", meaning their
dominant hand, and then continue to maintain it during any required movement and changes in body positioning. Especially if the upper body has to turn/twist.
Then, for 2-handed shooting situations, I look to make sure their
supporting hand isn't interfering with how their dominant hand is able to control things. A surprising number of folks don't appear to recognize when their own hands are sometimes "fighting" with each other for control and manipulation of the gun. It should be a concerted effort, looking to maximize the concerted efforts of both hands, not a "contest" between hands.
Then, I look to make sure the person remains properly balanced for conditions, whether static or dynamic for different moments, and
throughout any changes in conditions. Sometimes it can seem like it's trying to learn to walk all over again, but there's no reason the walking & moving (and turning, bending, crouching, etc) skills of a lifetime can't be used as the foundation. They've already been learned, practiced and ingrained, right? Just not for shooting and/or fighting, perhaps.
Attention to trigger technique and control has to be maintained throughout any changes in circumstances and body posture, balance, movement, etc. Doesn't do anyone any good if attention to one part of the overall "technique" means another part is allowed to be come sloppy, and misses result.
This is obviously where having the assistance of an experienced trainer can be helpful. Not only to teach good skills, and identify any counter-productive habits, but to help identify any problems as
learning occurs, and to make sure "new" parts of the overall techniques are built upon a solid foundation of parts
previously learned.
"Fixing" a problem with technique requires first identifying and acknowledging that it exists. The corrective
action can sometimes be easier than getting someone to
accept that there's a need to change something, in the first place.
Shooting, like the martial arts (isn't shooting a modern martial art?), is best built upon a solid foundation skillset. The more you progress (and want to progress), the more important understanding and mastery of the foundation "basics" becomes.
Just my thoughts.