Pinkies and fuzzies are good, all dragons love them and so do small moniters.....my frillies love a pinky or two.
I wouldn't bother going to much bigger, even though they can eat them, it shouldn't be a huge part of their diet.
$660? Hehe, I wish I could find people willing to pay that much for them, I'd be a squillionaire pretty quickly! I've been freezing kg's of the things at a time then feeding them to anything that will eat them. One of my bluetongues won't touch them any more, I think she's sick of them! Poor girl.