They do work for both crappie and bluegill although they really shine as a crappie lure. Personally myself, I almost never use bait while fishing it (especially for crappies) but there are others that tip it with a spike or waxworm. There are times when bait is needed for finishing off bluegills that aren’t aggessive enough to inhale the lure by itself. I’ve never tried fishing it in the summer although I see no reason why it wouldn’t work in the summer.
I usually fish a Mic or Cecil by slowly working the water column from just under the ice too the bottom until you get a feel where the fish are located.(of course if you have a vexilar it makes the location part easier) I jig the lure so the little flipper barely flips out while slowly lowering it. Sometimes the fish like a more aggresive jigging action too. LIke any other ice fishing jig you have to pay attention to what they like that day and adjust your jigging action accordingly.