20 caliber barrels, looking for advice

I am debating on ordering a .20 barrel today while the X-Caliber 20% sale is still happening. The options for .20 barrels are .20 Tactical, .20 Practical, and .204 Ruger. I've focused in on .20 Tactical because the dies are readily available and it's basically a necked down .223 so cases are widely available and free. For the cost of a barrel and a set of dies I'd be up and running.

.20 Tactical uses 32 and 40 grain bullets according to Wikipedia so I am thinking a 1:11 3 groove barrel should work nicely.

If the 1:11 twist sounds right, then I need to decide on barrel profile, length, and gas system length. On a custom barrel, am I correct that a pencil barrel should be just as accurate as a bull barrel (and any profile in-between), but a bull barrel won't get as hot as fast?

Any suggestion on barrel profile, length, and gas system length? Does this call for an adjustable gas block?

Here's the order if anyone is curious:

Configure Your Custom AR-15 Barrel
Barrel Steel: 416R Stainless Steel
AR Barrel Length: 20" [+$20.00]
Caliber & Twist Rate: .199/.204 (.20Cal) 1:11 Twist 3 Groove
AR 15 Chambers: .20 Tactical [+$50.00]
AR Gas System: Rifle Length
Gas Block Journal (Length): 1.92" Long Gas Block Journal
AR 15 Contours: SPR .980, .850, .750GB, .730 (Up to 24")
AR Muzzle / Crown: 1/2"x28 Threads (.20-.224), 11? Crown
Finish: Polish


I got dies and bullets ordered last night as well. I think I have a rifle length gas tube somewhere and probably have a .750 low profile gas block in a box. I have a 15" handguard, but might want something longer / different depending on how it looks with the 20" barrel.
I will need to figure out a suppressor for it. I don't have a spare .223 suppressor to put on it, and I imagine a rimfire suppressor is going to get eaten.