Currently, my arrows weigh low 400's as is with the 100 grain broadheads. I'm considering switching to 125 grains. Here's my delimma:

I'm trying my best not to lose anymore fps at the same time trying to gain a little knock down power. From what I've been reading here, it appears some of you feel that a heavier arrow will penetrate better and expire a deer in less time. My thought is that if I put the arrow where it needs to be, 100 grains will put'em down much the same as 125's will. A whole through the lungs is a hole nontheless. What are your thoughts on this? Also, will 25 more grains actually penetrate all that much better? Lastly, what cutting diameter would you recommend for a 400ish grain arrow? - I want to be able to pass through with the largest cutting diameter possible that will still allow it. (55lb draw at 200ish fps)