My amateur answer is that I average 45 mins to get a passable first RC print from a neg. I do drum processing and typically 2 or 3 sets of test strips per image, I haven't properly calibrated my printing yet but I do know what settings work well for my own film development processes. Taking a customer's negs is far, far more difficult.
If you're doing this professionally, you must be far faster; you need to make use of all possible automations because your time is the most expensive thing by far. You need:
- an automated print processor to minimise your dry-to-dry times, particularly while evaluating dodges/burns
- a fully calibrated f/stop-based print process, e.g. BTZS, so that you can read a few densities from the neg, dial in a contrast directly and know, on the first exposure, that you have 90% nailed it on any paper that you have in stock
- calibration across papers means you can prototype complex dodge/burn sequences on cheap+fast RC then (with tweaks to filtering and exposure derived from the calibration) repeat the print on FB on your first try
- automated print washing that doesn't interfere with your workflow
- a bunch of annoyingly bulky and/or expensve machinery like hot-air print dryers (for RC), drying racks and drymount presses (for FB)
- probably an ability to cut mattes and access to a supply of cheap pre-cut mattes with ~24x19cm holes
- probably an ability to print colour too
- name recognition backed by a bunch of gallery shows.
If you're not already running a photo lab, I don't think it's a business I'd want to get into. There's a reason all the pro labs are going out of business: who is going to pay $200 for a hand made 16x20 when they can get a digital one for less than 10% of that price? Let alone a $100 8x10 vs $3 digitally.