2 pellets and the one your shooting should be fine for deer. Put that in the right spot and the powerbelt will do the rest. I shoot 90 grains of loose Goex 2f and a 245 grain Aero Tip. I can not report on how they bring deer down as so far no deer has been willing to be a test subject. I use a RED DOT scope on my CVA Staghorn Magnumrifle. Most my shots are 50 yards and under. So I sighted in at 50 yards with the RED DOT. With my scoped muzzleloaders I sight in for 70 yards and one I sight in 2" high at 100 yards. This is my hay field rifle during the modern season.

Two pellets and a 295 grain Powerbelt will get you 1555 fps. That's moving pretty good for a almost 300 grain projectile. I can't tell you want three pellets will give because it is not a recommend load. If your dead on at 50 yards, aim for the upper part of a deer's kill zone at 100 yards. The little drop should put it right at near center. It is a shame you can not get to a range to try them out before season. I have some ordered but they are not here yet. Or I would run one back to 100 yards just to see what it drops..... sorry I could not help more.