Anne - First, I confirm that there was never, at Sowerbys or Davidsons, any pressing other than by hand up to "my" time and I would be 99% sure about later too.
Toughening (aka tempering) can perhaps be looked on as the opposite of annealing. Instead of removing most stresses high stresses are deliberately introduced by suddenly cooling the slightly soft glass. Cooling can be done by jets of air (e.g. Jobling and vehicle side and rear windows) or by dropping into a bath of hot oil, which is what Davidsons did.
A normal "melted" shop did the job. (Anne, for any new members interested, I've forgotten how to do a link to my posts on the subject in Nov/Dec 2004 - help, please!). The melter used a normal chair, raised slightly, and the bath of hot oil was adjacent. When he had finished the tumbler he simply tapped the punty to drop the tumbler into the oil bath. If there wasn't a loud click it was probably still in one piece! Baskets in the bath could be lifted out, drained and taken away.
Toxic, and now illegal, solvents cleaned off the oil. First rinse with, I think, xylene followed by vapour bath treatment with trichlorethylene. They were then quarantined in a warehouse for x days (about two weeks I think) by which time all those about to explode had, hopefully, done so. Someone in the past, perhaps J K Inwald, must have worked this out. At some stage they would have been inspected and very lightly ground on the bottom to remove punty scale. I'm a bit vague here as my day-to-day responsibility was only for the hot parts of production.
We only had one oil bath, and I saw no sign that there had ever been more although there could have been. We therefore only used one shop, who specialised in toughened tumblers although not full time. and therefore the maximum possible output at the time would have been 5 3/4 shifts, a week's work. I couldn't guess how many weeks p.a. we did. Now the tricky bit. I think (getting a bit vague now) that 1000 per shift at the press would not be far off, a little less for bigger sizes. Nothing anywhere near a pint at that time. I haven't a clue what the loss rate after that was.
So far as number of people goes, at my end there were seven, the (lehr) taker-in being replaced by the oil basket man. All subsequent work would be done in bits and pieces by the normal finishing staff of women and I couldn't guess on that one. Hopefully someone had it all costed but, as I'm sure you all know by now, I knew even less about that side of things at Davidsons than at Sowerbys.
No, Anne, I can't understand either how a profit could have been made at a sensible price - it probably wasn't!
Any follow-up questions welcome - I'll do my best.