any advice for maximizing the attendance at your team camp? Routinely I will budget it for 12k, and get D1 attendance for only 3k

Depending on where you are geographically, the team camp only has a radius of 500 miles (I think is the number). So if there are only 50 d1 recruits within 500 miles, not including jucos who don't go to the camps (again I think), only 50 will show up and you can't increase that. You could invite d2 and d3 kids to increase the number, but that's it as far as I'm aware of.

Edit: so if this is your Gonzaga team it means there are only 50 d1 recruits within 500 miles, which makes sense with Canada and the Pacific Ocean being a large part of your camp circle's area.