I worked my way through grad school (Pre digital) printing for a high volume custom lab in NYC. I had five enlargers in my darkroom and depending on work load I would set up at least three, and often all five. I was able to print scores and even hundreds of hand made prints a day. They used to say the expected rate for a good technician was ten negs an hour. Multiple enlargers and a good printing strategy will save lots of time. And, believe me, these were quality prints, with dodging and burning. (I didn't have to do the washing and drying.)