Giant Mealworms (Tenebrio Molitor) are NOT the same as Superworms (Zophobas Morio). Giant mealworms and Kingworms ARE the same, they are nothing more than mealworms given chemicals in their feed so that they grow bigger and won't morph into beetles like regular mealworms. Some of the online sites that sell them even say they are meant to be used as fish bait, not for reptile or bird diets.
Superworms can be used for hatchlings on up, IF you buy the correct sizes. I buy mine from superwormfarm.com, they sell them from small to large. The smalls are usually no longer than the width of a quarter, but they are skinnier than a mealworm of equal length at that size. My juvies and adults both prefer the medium size. My adults will eat the large ones, until one of them gets slapped upside the head by one as they are eating them LOL Some of the larges put up a heck of a fight it's quite comical sometimes.
Superworms are overall a better feeder for your Leos than mealworms, but I do also feed mealworms, a variety is always the best 
I'm glad to see someone else picks those large ones up with tweezers too LOL I just can't get myself to pick one up with my fingers, they give me the creeps LOL I don't mind the mediums & small at all or any of the other feeders I use, but man, those large superworms are something else !!
As stated on another post, Silkworms are the best feeders, but not readily available except online. They are a bit on the expensive side especially when you add in their special feed you have to use. I've heard a lot of good about roaches too, but I've not tried them.