On Wednesday evening I finally threw out the dead XTOL and got around to making some D316 concentrate and have processed one 35mm film. It worked! The film is drying so I have not yet scanned or printed anything. The negatives look normal, but dark, see info below. Some comments:
The quantity concentrate I made was for 5 liters. 5 liters required 0.25 grams phenidone which was the smallest amount I felt I could accurately measure.
1) I started with 17ml PG per liter, so 80ml total. I should have ended up with 110ml of finished concentrate, but instead ended up with 120ml. Now I used 8 mol Sodium Metaborate (3g/L so 15g total). Possibly this made the difference? Would starting with, say, 15ml PG per liter pose a problem?
2) Mix temp was 85C. Absolutely no problem dissolving anything and no signs of crystallization.
2) One liter of working solution was prepared using 22ml of concentrate as directed and 45g sulfite.
3) Resulting pH was 8.3. This was adjusted down to ~8.2 using dilute (5%) acetic acid.
4) The film processed turned out to be ORWO UN-54. I had thought it was Legacy Pro 100 (aka Acros) as that is what was marked on the casette. According to the Massive Dev Chart iPhone app, Acros in stock XTOL is processed for 8:00 min, which has worked well for me in the past. Multiplying by 1.9 (as given about IIRC) gives 15.2 minutes but I rounded and used 15. The processed UN-54 looks 1.5 to 2 stops pushed so it's a bit dark.
5) My time for UN-54 in stock XTOL is 6:30. Multiplied by 1.9 gives about 12:20, which judging from the results I would guess is about right.
So, there is some user feedback for you. I'll post a bit more once I have printed/scanned some.