RE: Realistic goal...20 fps better with new bow?
If you are already getting 272 fps, that is very fast at that draw length/weight. Will you get more? Maybe, but for what?
Run some tests and I THINK you will find the difference in speeds you are talking about, especially at hunting distances, the impact points will be basically the same, in other words, I doubt you will pick up any forgiveness for distance estimation. Where you might see the improvement is out past 40 yards, so it really comes down to what distances you are shooting.
If it were me, I'd rather use the "faster" bow to up the arrow weight while maintaining the same speed. Hits em harder to muscle through things. However depending on what you are shooting at, this also might be a non-issue. Just make it harder to pull teh arrow out of the ground after the pass through.