Number of workers is irrelevant in calculation. It would be the hashing power of each machine.
Maybe try using a calc and divide to the time frames you want.
By using the hashing power you can see how much it would earn daily then divide by that.
ie 60mh would make 0.001260 Eth a day if u want 10hrs then 10/24x0.001260 would be the answer.
https://www.cryptocompare.com/mining/calculator/ethAlso POW is paid for work done, so with Ethermine you have to prove you done work to get paid, It all automatically logged to what ever wallet you put.
Also work is generally logged per wallet then by machine.