I have spent the last three months training specifically for a one-arm chin. Because this skill puts a lot of strain on the elbow tendons, my program included a lot of joint preparation: high volume pullups, back lever with palms facing down to emphasize the bicep, weighted pull/chin lockoffs, and one-arm lockoffs/isometrics. I can now get a decent one arm (not quite from dead hand) consistently without any elbow pain.
I'm wondering if anyone else who can one-arm has experienced any carryover in strength of the tendons in the elbow when transitioning to other skills that are intense on the bicep (e.g. planche).