Before going to all that trouble, have you tried reversing the mag release, so that you can punch it with your trigger finger?
I have square hands, and short thumbs. By changing the mag release to the other side, I'm able to make a mag swap without having to shift my grip.
This, BTW doesn't work for me with the factory extended release, just with the standard.
Reversing the release is a simple job, which will only take you a couple of minutes. Give it a try, and THEN if you don't like it you can go the costs-money route and have only lost a little time.
