Closest to the pad combined with maximum altitude for 10 lb rockets is a bad plan. A landing "target" other than one close to the pad is a really bad plan. One option in the same weight class as the bowling balls would be a gallon of milk. This payload would present a different set of aerodynamic and recovery challenges, not to mention being easier to find than a 8lb urethane sphere.
Given the lower waiver, target altitude, closest to but, below 5280 feet AGL, or odrocs, tallest or fattest in a motor class, might be ways to go.
Most of the contests at LDRS22 were staged by and for First TV. The usual contest seems to be who had the "coolest" flight with the prize being bragging rights.
As far as organizing any contests, that will have to be done by somebody other than the hosts, they already have way too much to do.