How do I calculate the expected shares per minute for my pool

I am currently mining Zencash in a pool, and I’d like to be able to calculate the expected shares per minute for a given pool’s hashrate. Let’s say the pool’s hashrate is 50 KSol/s. I think that the shares would need to be standardized to some share difficulty, let’s call it one. The current block difficulty is 764,414.6217 (11.0 block reward). I’ve been digging around and it’s hard to find the math involved in this. Does anyone know how to do this for Zencash?