Thanks, useful info! That one has high gear teeth reaching middle of the intermediate, which would indicate 1.41 (what I thought to start with...).
I made calculations on another case that I have open, serial 28D meaning 1.22. Gear on gearbox output shaft is 26 teeth, both intermediate and high gears on center shaft are the same 44 teeth, and high gear on case output is 34 teeth.
Since intermediate and high are the same, we can discard them in the calculation. If I do 34/26, I get 1.307, meaning that you need 1.307 revolutions of the gearbox to get 1 rev out of the case... How did LR calculate their ratios?