Sprinkle groundbait on the micros once damp, i always use it like that along with some 4mm skretting pellets and that mixture has never let me down. I favour bait-tech’s mojo groundbait.

i would just give them a harder squeeze they always seem to return to tiny pellets

I think it depends really. If you want the feeder to explode on impact, then I don’t recon you need to bind them with anything. You will have to soften them though, and you will have to play around with how firm you compress them in the feeder. If you want the feeder to explode on the deck then its probably better to incorporate some groundbait. You don’t necessarily need to soften them if you just plug a hole less feeder both ends with groundbait. Or you could soften them and bind with some groundbait or dampened pellet powder and just use a conventional grip mesh. Depends really on what your fishing for and when.