An exchange seems good! It'll open things up for both of them. What themes from Geralt's past do you want reflected in Crane's memories? Geralt values people who are honest and straightforward - Crane is a manipulator but when he was lecturing at university he was straightforward with his teaching to the point of being harsh. I think he would especially value Crane's resilience - which suggests Crane rebuilding his reputation after being fired or surviving an especially difficult past.

If nothing like that suits I can pick something to match what you want to explore, no problem.