Matt,
Good luck with your surgery! Even if they need to do a graft, it won’t be the end of the world (though your mouth will hurt for a few weeks). My surgeon said that men who have a BMG are less likely than end-to-end patients to have painful erections because the urethral length is not shortened.
The catheter I woke up with after surgery and lived with for 2 weeks was 16 French. Don’t miss it at all.