They are spot on mate.
I use them with 2mm feed pellets soaked in lake water for around 2-3 minutes. Drain off the excess water, shake them well so that all of the pellets seperate.
Fill the feeder 3/4 full with the soakes 2mm feed pellets, place the hook bait into the end of the feeder and then add the 2mm soaked feed pellets to fill the rest of the feeder.
For the hook bait i use a 4-6″ hooklength from 0.12 – 0.20 depending on the size of fish you are after with a size 18 – 14 QM1 hook tied using a knotless knot with either a korum quick stop or a mozella micro band.
My best bait is a 6mm banded pellet or 6mm punched polony.
Try tank testing a few to see how much pressure you need to press in the feed pellets to see how long it takes for the release of the bait.
hope this helps.