Get your nose measured by a professional before you cut it off....
Given your general description of your height and build, I'd agree that you're very likely closer to a 13 1/2 LOP than a 14 3/4. If I were fitting it to you, I'd chop it down to about 14" first (for a double trigger gun) then 1/4 and even 1/8" slices as you approach what you think you need. When you get your mount feeling reasonable, start shooting it. I brought a 12" chop saw to the range once to do this. It's pretty hard to add wood back, but it can be done. Don't bother with putting a buttplate on it to shoot it. If it's painful, shoot lighter loads. Keep the pitch at something that is close to what is generally accepted, say something like 3",until you learn more about what your specific needs are.
