im sure loads will have there own way, but this is how i do mine and they all sink, stay on the hook after striking on the pole (and never come off while shipping) ive waggler fished them but not feeder fished with them, but im sure they will be fine!
i mix 2 sachets of dr oetker gelatine with 1pt of boiling water (double the dose on the packet)
i get the gelatine from summerfields/co op whatever its now called.
i use ringers expanders and have found the next generation ones to be the best ive found so far, the cool water ones have turned to mush at the sight of hot/warm water (but these are brilliant in winter on there own!)
pour BOILING water into a measure jug (1 pt) and add both the sachets, mixing with a fork to dissolve all the gelatine.
leave to stand for around 20 mins to cool down (you want it tepid)
put expanders into pellet pump
cover them with tepid water/gelletine
pump pellets and release so they all sink
leave for around 2 mins (this is the critical point, you want to see that they have expanded and it will all depend on the temp of the water, the warmer the water the quicker they expand)
i then pour the contents onto a riddle over a bowl
you can re use the left over water to make a few more
leave the pellets to dry a little on the riddle then bag em and freeze em for the next session

Buy some Ringer’s cold water pellets, 4 and 6mm.
Take a small amount, enough for the session, and put into a pellet pump. Fill with water so that the is only a very very small amount of air left in the pump.
Suck out the air so that the pellets sink.
Then empty into a bait box and tip away all of the water ….except for a tablespoon full of water.
This will soak into the pellets but won’t make them soggy.

You can then hook them straight onto a hook or spear them on a hair spike.