I feed mine on a regular basis as well even more perhaps than you lol. I feed my fat tails mealies, crickets, and waxworms daily. I feed about 5 mealies or crickets and then one waxworm. They seem to like it that way, and the speed in which they gain weight is a plus.

They aren't suffering and I'm planning on breeding them in the next couple weeks.

I keep mine in a plastic container on cricket food and cricket gel, they last a couple weeks. They are also gut loaded so they provide a bit of nutrition. I'm sure you could keep them in the fridge for at least a month, easily.