Help choosing suitable stall ratio for converter

That's a relief! I have just discovered that the original 727 converter was 2:1 and original engine delivered max torque at 2800RPM. I have read that stall should be about 500 to 700RPM below max torque so I seem to be on the money.
The engine now has a very slightly hotter cam than original so peak torque may be slightly higher than it was new.