hmmm lets see? where to start?
you're right mealies and supers aren't the greatest food you can be feeding him. Silkies are one of the best live preys you can feed him although they tend to be a bit fatty.
if you want him to eat crix, try giving him smaller crickets and in smaller numbers at a time. he may be more interested then.
as for eating every three days, this is ok for live prey. but I want to make sure that hes getting greens(mustard, collard, and turnip greens) and veggies offered fresh EVERY DAY.
For a great list of food items to feed your dragon go check out www.beautifuldragons.com. This is probably one of the best nutritional sites on the internet right now.
Derek