I have always wet sanded. Depending upon severity of the orange peel, 1500, then 2000, 2500 and 3000. Don't go flat with the 1500. Just use it to get most of it out. Flatten with 2000, then remove the scratches with 2500 and 3000, then compound by machine, for the most uniform results. Then use a DA like a Rupes, Flex, Griot's, ect to remove any ultra fine buffer marks.