We've got 28 entries I think this year with the HS students. We don't have lessons, and honestly pull-out time is not something that's feasible for much of the year with only two of us and marching season. At least in our situation I consider that to be a strong number as that's about 40% of our band.
My other thing that's helped us a lot is having an Applied Music class where we can focus on this a lot. I know of a director that retired that would regularly end up with four or five All-state kids with those same resources by leveraging two of those classes. (She was a total master with that)