I believe I'd concentrate more on his proficiency than on hours spent. The problem I see with hours spent is he's only shooting for that purpose, hours spent. If you'll set standards and make him strive to meet those, he'll be shooting to get better.

I believe that I'd figure out how many pounds he's pulling then figure a deadly range for that weight. I would then make him shoot at the maximum distance consistently in the kill zone. I'd do this from several different positions as you never know whats going to happen during a hunt.