A year or so ago I thought it would be fun to make a straight English-style stock for a 20 ga. Nitro Special. So I ordered an inexpensive semi-inletted butt stock. (I forget the supplier.) My biggest problem was cutting the pistol grip off so that everything would look right. With that solved I proceeded to make things fit (heading up?). It turned out pretty well and it was satisfying to accomplish.
My work experience is similar to yours, so I'd say your skills are more than sufficient to do the job. Just be patient, go slow, check fit often, and make sure you have really sharp tools.
I wouldn't waste money on any "custom" stock prep. I've worked with a number of "semi-inletted" stocks over the years without any serious problems and found them to be good value as long as you don't want fancy wood and have reasonable wood working skills.
R.
