I used to keep both a dwarf fuzzy lion and a japanese bluefin(heterura):
I trained my lions to both eat pellets. The advantage being that dry food absorbs a lot more liquid supplement. I still fed marine silversides as well though.
I still think the verdict is out on a lot of these food supplements, but they can't hurt IMO.
As for longevity in regards to your Rhinopias, I wonder how much temperature plays a role.