While not definitive, I have done a few comparisons of 777 2 and 3 F and Pyrodex P. Using 54 PRB the 3 powders were only showing slight differences in velocity. With 50 conicals the 777 2F shot slightly faster than the 3F and the Pyro P was a little slower but not by much. In most rifles the slower load will shoot higher due to muzzle rise, this is fairly common.

I would go with the one that gives the best accuracy and not worry too much about the velocity, the differences will not make enough difference in trajectory within normal hunting ranges to worry about.