This is where I need to jump in again.....
I think we are to the conclusion that momentum is most important and the question is what speed can you have while maintaining it.
If with this statement you mean that momentum is important but also that a certain level of speed is necessary in order to maintain a relatively flat trajectory then I agree with you.
However, if you are implying that a 650 grain arrow traveling at 200 fps is in some way " better" in terms of a total practical hunting setup in comparison with a 425 grain arrow traveling at 270 fps then I really have to disagree.
Again, it takes a moderate amount of speed, kinetic energy and momentum to work in tandem in order to create more of an ideal combination for a variety of bowhunting situations. As I made mention of in another post...what good is alot of speed without the mass behind it to provide penetration?...what good is a ton of mass if the arrow arcs like a rainbow and the archer cannot judge distance?
You need a good combination of all three of these characteristics in order to have a good all-around setup.