One must understand there is a big deference between competition "stance" and combat "stance"
Competition is simple. Get comfortable, natural point of aim, don't muscle the gun (rifle or pistol), keep head up right. That is the three critical parts. comfort, NPA, and head straight and up right head.
So we can't say what's best because we are all different.
Now to combat stance. What combat, home evasion, knocked on your butt at an ATM, car jacking, LE or military.
There is no one stance fits all here. Take a recliner to the range, shoot from the laid back propped up position. Shoot from your back laying on the ground up at the the target. Shoot from the drivers and passenger's side of your car.
Get a table and chair and take it to your range, practice your stance from setting behind the table.
Shoot one handed, left and right from different sides of a barricade.
Put your gun away, go to the barricade and point around it using your fingers. Use a two handed grip pointing on the left and right side. Then use our strong hand on both sides, use your other strong hand on both sides. Then right hand only on right side, left side only on left side.
See which method exposes less of your body.
Using the three categories I mentioned in competition builds a good solid stance.
There no one stance in combat or self defense. The only exception, if possible, is the stance which exposes the least amount of your body to the target.
CPT USAR Ret
USAMU Sniper School Oct '78
Distinguished Rifle Badge 1071