[Mark Yacavone]

That's insider information, James. j/k

Actually the charts and graphs I've seen have to do with the GM 245 mm core, which is a step larger than the old Opel standby. There are about 8 different factory impellers (fin angles) plus 4 or 5 stators, so it's kind of a mix and match deal there.
Not so much with the Opel 8".
There's really only a couple of stator designs, so they have to be machined to fine tune the combination. The fin angle starts out basically straight ahead or neutral, so it has to be adjusted within it's workable window.
There are a few more subtle tuning tricks but you're always walking a fine line there.

Seeing a torque converter multiplies torque, it stands to reason you would want to multiply as much as you can. Sometimes that flash point wants to be a little over peak, at it, or a little under, but yes, right around it it.

No dyno sheet , but with a popular combo? Usually no problem, with a large enough data base.
Odd ball or Dime Rocket type combos? That's where a lot of S/SS racing experience helps, but also a s.w.a.g. sometimes.

Gotta give the carpel a rest, but specific questions?