Also, consider (and practice) your draw from the holster. Depending upon your weapon and the design of the holster, it is easy to 'Strap Trap' yourself until you have practiced with it some.
You will find that with 'most' holsters and most weapons...you will not want to try to immediately get a 'full' grip once you've un-snapped the thumb break. If you do...you'll end up with your thumb on top of the retaining strap, which will stall (or completely stop) your draw.
With 'most' holsters and weapons you will need to retain the weapon using the pressure between your fingers on the grip and your palm (at the thumb) UNTIL the strap has cleared the weapon. At which point you can orient your thumb and complete your normal grip. Done properly, you'll have a complete grip on your weapon long before the muzzle clears leather.
Its sounds awkward...but will become seamless IF you do it each time smoothly and resist trying to speed draw from your thumb break.
Re-holstering (again depending upon design) can end up being a two handed affair, just be aware. Take your time re-holstering and don't get the strap (or anything else) inside the trigger guard (Glock owners).
