I've run into the length/girth issue a lot. I find it best to reach out to the shop/receptionist ahead of time to check is the girl is ok with your size.
Also getting recommendations from other punters.

Certain positions can be off limits until repeat visits, If the WL is willing to see you again lol. Plus you have to go super gentle which can be a buzz kill. I'm always looking for a WL who will let me go hard. Currently that's just Rebecca from 278 but I haven't been punting a lot or seeing different girls.

I once had a sesh where after I took my pants off the WL was like "yeah nah" and left the room. I was offered another girl who came in got be hard and also bailed lol.