Well, I can only go off my experience so far and talking to other doctors. I'm seeing a psychiatrist and after three sessions and two psychological tests (all in about one month) he says I'm ready for T. He sent me his approval letter to give to the endocrinologist today. So basically I was permitted to go on T after a month, it just took time to find an endo. I still plan on seeing my psychiatrist again, at least until I come out to my family. I'll need help with that. My insurance paid for the test and pays for my sessions with him.
There's only one endo in my area that will prescribe T to transmen and he's not on my insurance, so I'm going to have to pay out-of-pocket. His prices are decent though and supposedly my insurance will cover the blood tests. How long it will take to get on T through the endo I don't know yet.
From the different doctors I've talked to who do top surgery you don't need to already be on T to get it done. Most do ask for a letter of approval from a doctor- I'm assuming from a psychiatrist/therapist and/or GP.