My son is doing great with potty training but we still put him in a diaper for nap and overnight. I need to order more "diapers" and I am wondering if I should get him something completely different looking going forward - Should he nap in pull ups? Should I get him overnight diapers so that they look different from his old style diapers so that he knows he's all done with diapers? I'm just wondering if he only had Cars or Thomas pullups or something it would further remind him that he's all done with diapers. What did you do that worked?