2-4-hooking prefers the full sized B50, for my Hill style bows that I have, I have not found a night and day difference by going to fast flights. A touch less vibration and a touch more speed. I tried a few shots with a padded FF on my Schulz, not much advantage at all, maybe just a tick faster. With my other bows I had the benefit of going to a 145 head from a 160 head on the same shafts when I put FFs on them. Not that I was planning on doing that, that is how the strings effected my spine requirement. It seems that some bows get more benefit from FF strings than others.