All these estimates of being able get a roll of film processed with hand-manipulated means in 15 minutes or so do not map to my experience processing film for the past 50+ years at all.
I might get ONE load of film through the develop-fix cycle in 15-20 minutes, sans wash, but there's still time involved in cleaning/drying the equipment for the next load, and there's work to do to move the processed film from wash to drying ... never mind space to dry eight rolls of film simultaneously (and without damaging it) if you're using an 8 reel tank system, plus time to take it down after it is dry and put it somewhere safe, etc etc. Oh yes, and there's loading tanks, etc, on the front end: it takes a while to load 8 reels no matter what else you do.
The best I've ever gotten done was when I was the chief of the photo staff in my High School. I had three other guys in the staff in a 12x20' sized workspace, partitioned into three small rooms (one an office, middle room for drying/cleaning, back room for printing and tray processing; two latter rooms both capable of going dark). With four of us working the processing in a coordinated way, we processed about forty rolls of film in about six hours time, using 4 and 8 reel tanks. That's a FULL day with four people working their butts off loading, cleaning, drying, preparing chemistry, running the washer, etc etc, in a facility (just barely) big enough to do the job.
I doubt very very much that any single individual is going to process more than ten to fifteen rolls of film in a day no matter what unless they have a continuous flow processing machine at their disposal.
IMO, it's better to think of the problem from the practical realities of getting the job done effectively and estimate the time to do it conservatively. With my current setup using four reel tanks, I have time and space to process about four rolls of film in an evening, dry to dry. With a fully automated scanner, that's about 35-40 minutes per roll of 36 to scan ... You can set that up to run while you're processing film and maybe just keep up after the first night's work (doing the previous night's developed film). If I have 300 rolls to process, that's 75 evenings worth of developing time; if I could get eight rolls done per evening, that's still 38-40 evenings' work, and you'd be behind on the scanning at the end.
For me, that's just too much time. My time is valuable too, at least as valuable as my money. Send the stuff out to a good lab and pay to get it done!
🙂
G