To keep rhinoceros beetle larvae only three things are required:
1. Good Substrate:
2 Good containers:
appropriately sized as shown in the picture below (camera film container was used to keep L1, 5x5x6cm tubs can be used to keep L2s, 14x10x7cm Tubs to keep L3 Females and 20x12x10 cm container for large L3 males). The bigger the container, the more substrate you need. Also the larvae are used to being in tight spaces - in the wild they live in crevices in rotting wood. These sizes was designed for the large species Dynastes hercules hercules so they will work for any larvae.
Containers should be made of a strongish plastic and you should make several small holes for ventilation. I use a heated needle to make the holes as drilling can leave sharp edges that can harm the larvae. Also note that the larvae are strong - they can push the lids off containers its for this reason I now only use containers with Screw on lids, as before it would not be uncommon for a larvae to escape.
You need a lot of patience, as some larvae take over a year to fully develop and become adults. Keeping a record of the larva weights is a good idea. They dont mind a small amount of handling but don't leave them out of the substrate for too long as they dry out and they don't really like the light.