Definitely get a reversal surgeon who treats PVPS guys. Last thing you want is getting a vas-epi reconnection, which could make things worse. Where are you located?
As far as 85-90%, that is highly misleading. About 85-90% might get ‘some’ improvement, but if your pain was a 10/10 before and you went to a 9/10 after, then that’s considered part of the 85-90%. I’d hardly call that successful.
As far as being pain free, or significantly improved, the odds are about 70%. Parakattill says about 69%, Tandon, Sabanegh’s research about 70%, Jarvi, 75%.
There is of course a very small chance of getting worse. It’s rare, but it can happen.
If you’re concerned about staying fertile in the future, then bank your sperm once you’ve returned to fertility, and if you want kids in the future, you can use the sperm you’ve saved. It’s pretty cheap IIRC.