I’m just trying now… (hard to tell where the mixture leaver is but will screenshot. I’m running the NXi so don’t have access to our engine pages (hopefully WT get these sorted at some point)
At the moment I am pulling back the mixture and watching manifold pressure, rpm and fuel flow until it rises/drops. When drops I enrich a touch and leave it at that. @jonasbeaver might be able to give more insight.
Climbing up that high is slow. Just testing and at 13400 I’m down to 300fpm, 14380 I’m at 250fpm. You basically need to lean every 500ft. This is a great post that helps [HOW-TO] Best Practices to Fly Bonanza G36 - #3 by Darrlyn1971
Don’t forget our bonaza has a normally asperated engine so flying in that rarified air is fairly hard for it. She is much better between 8k and 10k with nice thick air. 
Climbing
Level at 14600
