Hi,
1) you may check my program WifSolver to see if it helps.
https://github.com/PawelGorny/WifSolver2) in your case I think it is possible to convert program into task for BitCrack. Using Gpu solution will be find much faster. Let me know if you need help with configuring bitcrack - how to configure range start/stop, stride etc
3) BUT! If you say that you know publickey, we may use even faster solution, Kangaroo. I have prepared a special version of it to work with custom stride, somewhere on the forum I post explanation how it works. If it works, for 10 missing characters result will be done in VERY reasonable time.