next fall i will be shooting a diamond at 50-55 pounds and 25-26 in draw what kind of broadheads do you guys recemmend
Anything that you feel comfortable with. One that flies good might also be good, but then most do. I have taken deer with most out there including Slick Tricks, Magnus, Rage, etc... But I shoot the Montec. All of these are good heads and will do their job if you do yours. Since you are shooting a shorter draw and only 55 pounds, your KE will not be astronomical and you should consider a cut on contact head. I would also shoot a fixed blade head if I were you, but that is preference. You are going to see a lot of guys tell you what to shoot, but it only matters what you feel comfortable with.
You could stick with your thunderheads and do just fine. Whatever you choose, I would keep it fixed blade, and if you really were worried about penetration, go cut on contact, like Magnus stingers, or muzzy phantoms. etc.
With the speeds you'll be shooting (not being too GREAT), I wouldn't overlook these 2: 1. Magnus snuffers. 2. Wensel Woodsman. You're producing enough energy to propel these two 3-blade heads.....and the beauty of them is their price tags. You can get SIX heads for less than $30. You'll need to do some supplemental sharpening on both of these choices (IMO, neither is hunt-ready - out of the box). But, I consider the task part of the process.......and a minimal time expenditure for the cost savings realized. Good luck.
As much as personal preference is a valid point when choosing BH's......the above (or any other mechanical) is NOT what you (OP) need.