Eating 90 crix a day just makes for larger poops, not a healthier dragon. If your dragon is eating more than 30 6 old week crix, or the proper size, a day, you are giving him a eating hobby, not nutrition. I know there are some who take pride in their dragons eating ability, and apparent health. I have found that you just end up running a lot of extra food and money into the poop scooper.
Like most breeders we do have a vigorous eating regiment for babies and juvies, but as they get older you don't add to their genetic ability to grow by feeding them excess food. I think it is pretty clear by watching a dragon grow, how much you should feed them.
In fact, I have seen dragons grow a couple of inches while brumating for 4 months with no food.
Just like with people it is important to eat to live, not live to eat.
Jeff