A crosswind join over the numbers is part of the standard ovehead join. I wouldn't go overboard on the R/T though. "G-XX, Airfield in sight, joining cross-wind." should be sufficient. Much more important to listen out and look to ensure you know where the other circuit traffic is. Joining crosswind, your conflicting traffic will be either taking off, or be on the downwind leg. If you are listening out, you should be able to integrate with the other traffic easily.
tp