the castings will always be quite wet, it's what keeps them happy - the feeding method cn help with harvesting, if you always keep the feed to the top or one side of the bin it keeps the worms in a more limited area .... also when you're coming up to harvest time you can put feed into on of those orange mesh produce bags [oranges/onions, etc] and put that in one corner - in a while the majority of the worms will migrate into the bag, and it can be set aside while you deal with the rest of the bin

depending on the quantity of material and size of your bin, you can dump it out on a large piece of cardboard and mound it up - scrape down the surface layer a bit at a time and return any worms exposed to the bin - as you work down the pile the worms will dive and congregate bottom center, so eventually you'll be left with a ball of worms in the remaining bedding, which goes back in the bin ... be prepared to get your hands dirty or wear cheap plastic gloves

if you can stand it, you can also watch for cocoons and return them to the bin as well

Bill