Yes, it will weight more, but only about 20 gr which is insignificant. However, that will increase momentum. FOC will lower slightly, but so little that it will not matter. I doubt would notice a difference between the two, except that the ones with the proper dynamic spine will shoot better.

It's always important to shoot an arrow at the proper dynamic spine needed for your setup. Keep in mind, there are a few ways to arrive at the same point. If it was me, I'd add weight to the front of the shorter length to increase FOC, while keeping arrow weight approximately the same. (I'm guessing that like most, you don't want heavy arrows). Remember, dynamic spine is weakened by adding weight to the front, increasing draw weight, or by shooting a longer arrow. Adding an extra 25 gr, or more, to the tip, may allow you to shoot them and inch or two shorter.