Ok, so first strikes are a go, what about alternate calibers? .43, .50, .62? My suggestion is to allow them if they chrono in field legal speeds.
What about doing something like Blitz, and allow BYOP for a higher day rate? $12 if you use field paint, $20 if you use your own paint (including first strikes and alternate calibers)?
Just some suggestions. However with Walmart just down the road, it may not be feasible.