I just leave snails and hermits in my tanks.
My G. Viridis seems to eat a snail every 2 or 3 days, with me offering a small piece of shrimp/silverside about 3 times a week, always in smaller pieces. Of course, I have a positively huge bed of worms to eat leftovers...
The G, Platysoma eats sparingly, but i just saw that he is holed up tight, so he might be molting... He munches hermits, has eaten one snail (with 3 or 4 more in there). He also ate silverside, though he initially pushed it away. I pushed it back, with a 'that's what there is for dinner' attitude, and the reluctant brat ate about half of it.
My G. Teratensis is a voracious eater. She has decimated something like 10 snails, a fiddler crab and several servings of silverside since i bought her a week ago today. makes me wonder if the LFS guys fed her much at all. She is pretty big, and a girl's gotta eat and all...
-Ron