[gilfo]

Is there a different way to align your thumbs for the different shooting stances mentioned above.
Weaver thumbs ointing up next to each other
Isosceles thumbs point straight along the slide?

I was told it make a difference for the two.

[danf_fl]

IMO (worth about $.02), No, do not change how your thumbs are base on how your arms are.

I use the same grip for revolvers, semi-autos, single shots.

Thumbs forward and no finger on the front of the trigger guard.

[Rentacop]

The grip need not change based on stance .

It is recommended to shoot with thumbs straight on a semi-auto but locked down on a revolver to keep a long thumb away from cylinder gasses / debris .

[msup752]

My grip changes slightly to match the pistol but not the stance.

Speaking of stances, isosceles and weaver were the two taught at my police academy. The instructor was quick to point out that in a high stress shooting scenario, officers always use isosceles regardless of what they were trained. I picked isosceles as my training stance. I would guess the key part is stress and that reverts people back to the basics.

[Rentacop]

msup752 :
There is at least some truth to the claim that the Weaver Stance falls apart under stress. There are also cases where cops under stress used the Weaver Stance. Massad Ayoob reported that Ben Grogan used it in the FBI Miami shootout and I saw a video of a cop using it in a shootout somewhere .
Jeff Cooper taught the Weaver Stance partly because it offers better recoil control, something that matters more with a .45 1911 than with a Glock 17 9mm .

Boatman favors the Weaver, saying the Isoceles plants you in place like a human pepper popper . Many others favor Isoceles ( Pincus, Jarrett etc. ) , so the debate goes on .

[rebelcowboy]

I prefer the weaver I can maintain better control on recoil and stay on target until empty if needed