Mike,
I’ve used it but not for ice fishing yet. I hammered some large mouth bass with it this summer. I forgot what they called that one, it was like a nightcrawler with the twist tail… Fished it a couple different ways but actually had the most success on a slip bobber, fishing the current from an incoming stream on Battle Lake. Just double hooked it it the middle of the body and let it wiggle around under the slip bobber, flowing in the current a bit. The bass loved it. I also lindy rigged it on Spirit one day and got some smaller walleye.
One thing I would stress is treat it more like live bait. Don’t leave the product exposed to air or sun. Zip the bag/close the jar and keep it in the shade. Obviously not as much of a problem in winter!
I would think the smaller grubs might work for ice fishing. GULP has one hell of a scent to it and it is supposed to permeate the surrounding water more readily that other scented baits. If you try it, let us know how it does under the ice please.