I went to CFI school in vegas, had BL for my initial and the single add on, really nice guy. Frank is really not a bad guy, just weird. My advice real quick, absolutely stay on his good side, always always always be early, for everything, the 10 minute break is a 5 minute break etc. if you get called on in class answer quickly, correctly, and concisely. If Frank has any doubt as to you passing, he will make you do a ground lesson with him and he will just tear you apart and you will not get the sign off. The whole battle seemed to be getting Frank's sign off, after that it was all downhill. Dry fly and talk your way through everything.
Looking back, I don't feel CFI school prepared me for actually teaching whatsoever, but without the certificates i wouldn't be where I am now, so just do whatever it takes to make it through, you'll be glad you did.
Good luck!