I'm from whole hog country and I've cooked many split and laying flat. Start with skin side up and flip about 8 hours into the cook would be my suggestion. Hog would be wrapped between two pieces of hog fence. I have seen people try the rotiserie with mixed results. As the hog gets more tender it tends to want to come off the spit unless you wrap it with wire fence. And you'll still need to foil the faster cooking parts to prevent them from drying.
You say cook to 180*, but where? That's always the question with a whole hog. The shoulders need 190* IMO, but that's going to put your mid section over the top as far as doneness. Better use the foil.