Walt's list in Walt's book shows 1924. Walt's list differs from some of the others because most of the others are repeats of the same list, complete with errors. Walt's list corrects these errors as much as is possible after this many years.

I'd stay below 8,000 psi pressure just because it seems to be the most often recommended. You'll be fine at 7,500.

I'll throw a few stars at you to welcome you back.