Robert,
I used a 4 MOA red dot for IHMSA SB & FP last season on my T/C 10" Match .22 LR & .32 H&R magnum barrels. However, I am thiniking of going to a scope on both just for the magnification capability (the eyes ain't what they used to be!).
I use a Taco hold and a rifle scope will work fine for the .22. I also have a 7mm TCU barrel that I have a 2.5x shotgun scope on it that has a 6" eye relief, which allows me to Taco that without denting my forehead. A rifle scope for a BB won't typically give you enough eye relief resulting in multiple cuts, dents and openings in your eyeball or forehead. A pistol scope has TOO much eye relief to let you Taco it.
If you are just starting out with offhand, unsupported, scoped-pistol shooting, let me warn you about magnification - you get into too high a power and you will never settle in and take the shot. It'll look like you're in an earthquake. My advice is to start with single-digit x factors and as you build confidence and ability, move into the double digit powers. Bret has been doing this for some time and he's got it down pat. I tried to shoot at 16x offhand and it took me forever to get on target !! In time, I'm sure I'll work up to higher powers as I transition from 1x red dot's to scopes, but for next year - I'll be under 10x on all barrels ! A good reason for buying a zoom scope - you can grow with it.
And ditto on what Bret said on ammo - TRY it ALL out. I've testing ammo that cost .90 a box up to that costing $5 a box. The $5 a box stuff grouped a hair better than the best cheap stuff, but not enough to justify the cost. Guess what - the best I found in my barrel was $1 a box. They all vary. Just because your buddies' .22LR Match barrel loves CCI Match, doesn't mean yours will ! Don't discount the cheap stuff. Remington Thunderbolt and Federal Lightning give me VERY good groups. At around a buck for 50, you can't go wrong !