I currently brought back my entire team and the carryover + post-season $ that comes with it into this recruiting cycle. I know if I do nothing it fully carries over. That said, If I chose to drop a player and sign someone with a portion of my carryover money does the remainder of my cash carry over completely or does that trigger the tax man to take a big cut ?

You only get to keep 100% carryover if you don't cut anyone. 

Got it, thanks