I think that as long as you are inside the engine's prop range you can take 1" diameter and add 1" pitch or viceversa, when you get out of that range, you start taking 2" pitch for each diameter.

Example:

TT91FS -> 11x10 to 13x9 (as the manual says)

11x10
12x9
13x8
14x7 <- we're out of the engines specified range, start decreasing 2" pitch for each diameter
14x6
15x4