I agree, even with the .30 ST barrel in my Bobcat Mk2. Somewhere in the .037 to .038 range works out well for holdover in Strelok Pro, and I'm shooting them at 885 fps. Even though the gun shoots the 50.1 grain pellets at 850 fps, which is 35 fps less, I have less drop at 100 yards than the 44.75 grain pellet at 885 fps. The BC on the 50.1 grain is just so much better, and accuracy is about the same. I think the BC is somewhere around .050 or maybe a bit more or less... So if your gun can shoot the 50.1 grain pellets, there is no reason not to go with them, since the price is the same as the 44.75 grain pellets. Plus, the FPE is higher!
I can't say all the above holds true for the STX barrels, or for the LW Poly barrels. Don't have either. But I do know the guys that shot .30 at EBR from an ST barrel last year shot the 50.1 grain pellets, at least the guys that I asked...