the "7.5" cell should be front and the 11" rear for your 7.5 focal length
So, to have the 7 1/2" I have to use both cells: correct ?
on 2 the front cell is your 14" cell
Mmm, I'm confused: if I remember well, there was only the 7 1/2" cell, in front of the shutter. I'll check again...
Use the gear scales on the bed when setting up, and it should work okay. Do you have gear scales on the bed?
Unfortunately, no gear scales. But I'm sure that the number of the gear (that is, the number of teeth) depends on the focal lenght and on the distance (not sure about the speed), according to some cryptic "formula". The problem is the formula... Having it, you can use different lenses...
I agree that 25 gears are really execessive, most of them have a notation about the focal lenght and the distance. This is the list: 95, 94, 93 (120mm, inf.), 92 (120mm, 120'), 91 (120mm, 34'), 90 (120mm, 19'), 82 (135mm, 20'), 81 (135mm, 14'), 67 (165mm, inf.), 66 (165mm, 20'), 65 (165mm, 14'), 60 (7.5", inf.), 57 (7.5", 28'), 58 (7.5", 19'), 55 (7.5", 15'), 40, 39, 38 (11", 60'), 36 (11", 21'), 34 (11", 14'), 29, 28 (14", 60'), 26 (14", 22'), 25 (14", 17'). The fans are marked 1/4 and 1/12 . Probably, it's a collection of gears coming from cameras of different size. Quite interesting, but this doesn't help.