Sparky, there are a lot of debates over whether kinetic energy or momentum are more important in flinging arrows. They both measure something similar, but go about it in different ways and arrive at different answers, with one putting more emphasis on a projectile's speed and the other on its mass. As was said above, there are too many variables to worry much about it at this time. Yes, it is possible for two bows to shoot the same arrow, but it is also very possible that they may not, again, variables.
As was suggested above, get into a bow that you like and can handle, 45 pounds on up will suffice for deer. Lower poundage can also suffice but if you can handle it, many here will suggest going higher rather than lower.
Match that bow with arrows of the correct spine and of about 9-11 grains of weight per pound of bow weight or pull. Again, that range seems to be a popular consensus of optimum arrow spec's. Then, practice, practice, and practice some more.
Once you can hit what you are aiming at at reasonable distances, you should experience no problem getting good penetration on a deer sized critter, and that is the name of the game. Hitting it well, and getting enough penetration.
Anything more than that is icing on the cake.
ChuckC