Yep the maths is pretty much correct. All you need to know is the angle (32 degrees) and the radius of the pulley (centre to outside edge of the pulley). Assuming the radius is r, then the distance you need to measure is a straight line from the notch (yellow dot at top in the handy attatched diagram) to the new timing position (the orange line).
To get this new distance (dist), you need to use some trig:
dist = 2 x sin(angle/2) x radius
so for a 32 degree position with the radius at 150mm (it's dark & I'm not going outside to measure it!) you would have:
dist = 2 x 150 / sin(32/2) = 83mm (the orange line length)
This gives you a straight line meausurement. If you wanted the arc measurement (ie from notch to new position around the pulley rather than direct line) then use PI...
arcdist = (angle/360) * 2 * π * radius
so for our example above:
arcdist = (32/360) * 2 * π * 150 = 84mm (rounded a bit!)
