FWIW, I have had broadhead tuning issues in the past, but it was only because of my arrows weren't tuned. If I bareshaft my arrows and they are flying like darts, it wont matter, period. I have shot the huge tree sharks on 3-3" feathers. The simmons interceptor is the a great head and I've never had any problem getting them to fly.
Michael, I'd bet your WAY over spined remembering you asking about a .300 spined arrow a couple of weeks ago. I know 2 examples to go by.
1. Curt Cabrera shoots a .340 spine(if I remember correctly) out of a bow around #60 with the big jim 300 grain 3 blade on front.
2. Chris Spikes shoots around #62(if I remember correctly) and he also shoots a .340 with a brass insert and the 190 grain tree sharks, so both of those guys are shooting right at 300 grains up front from a #60 bow and are shooting .340's.
(just thinking out loud here)