I have bought two HS Precision stocks and I have not had any trouble at all. I am very pleased with the quality and accuracy that I have gotten. I have never had the need to contact customer service though, so I can't really comment on that. FYI neither were cammo. I cant remember the model...
So if I am understanding you correctly, I want to use it as a mil-dot scope and use my mil-dot master, set the power level to 12. Is that on the 12-42 or the 8-32. I guess I could cut a 3.66 in strip of paper and post it a 100 yards and figure out the setting myself. Does that make sense?