A good rule of thumb with most frogs (frogs, not froglets) is to feed as much as they will consume in a few minutes and watch their weight for the first week or so. Provided the frogs are at a healthy weight to start out with, you'll get the hand of how much to feed quickly. Just err on the side of over-feeding in the beginning (frequency, qunatity and duration), until you're sure they're getting enough. Be sure to watch out for any one frog or frogs that seem to be getting the short end of the feeding stick. This can be common in trio-type situations where there may be an odd man (or woman) out of a pair. Good question--good luck!