I wanted to share with you how I kept mealworms going when I had 20-some leos.
I used one of those plastic 3-drawer units. The whole thing was a little bigger than a one foot cube, square. One drawer was my feeding drawer, the next a growing drawer and the last, the beetle drawer.
Each (or every other) day when I'd feed the leos it only took a few moments to look for pupae. When I'd see them, move them to the "beetle" drawer.
Once I'd start to see young mealies in "beetle" drawer, that would become the "growing" drawer. They look like little pieces of orange sewing thread against the oatmeal. Then, I'd make a new "beetle" drawer, starting with the leftover live ones from the last beetle drawer.
Occasionally, I'd run a little low and need to add a 500 cup to my feeding drawer but for the most part, it did well. (And sometimes for space, and/or bedding usage, I'd dump the feeding and growing drawers together.) Keep in mind that I had at least 20 leos, but for 10 or 15 it probably would have been sufficient.
I already explained how to mix the bedding and you'll really only need to do a fresh batch when you set up each beetle drawer. You'll figure out how much works best to get them through without having to keep adding more...but remember to always keep the drawers open about an inch for air circulation!!