The main idea is to get participation. As Joe said, you can combine Class I and II awards, but still allow a person to enter both classes. However, they would only be eligible for one trophy. If it will encourage people, you could have sportsman and expert classes in profile, 15, and CL I/II. And like Eric said, you could also allow people to make official flights in ANY recognized carrier class, just to earn a position on the NCS top twenty. I'd love the opportunity to fly my nostalgia profile Crusader, even if it wasn't a trophy event.
I'm not sure about big deviations in the aircraft requirements, however. If you want to allow 40 FP's in Sportsman profile I would consider that no big deal, but for example if you want to waive the profile requirement, or the minimum wing area, for Sportsman profile, I think you would be better served by having a Sportsman Class I event.