I am no x-pert by any means, but I have found that by either trimming brass to same length(after resizing)and then loading, using a very light roll crimp I am able to squeeze the most accuracy out of the load for the 50. "I" prefer a light roll crimp over taper crimp. 25 on in do not bother to do this. Most folks say no need to trim at all. This pretty true with a straight wall case and may not matter that much at all. With a taper crimp no need to do this. With the same uniform roll crimp I think can effect bullet pull and pressure provided your powder drop uniform too. Try to use same headstamps also, because brass thickness will also effect the crimp. As always experiment and try and see what works for your gun. I recommend seat bullet first and then crimp. Make sure the flare is enough to eliminate shaving lead and deforming bullet.
My opinions, others may have other ideas and suggestions that are better. Try everything and use what works for you.