The choice of hardner and softener is really what you up to you. I like my worms very soft but quite dense so they fall faster. I get most of my stuff from www.del-mart.com. You can get a plastic additive kit that has hardner and softener as well as scent. The main "staple"colors are Jnebug, Watermelon, and Green pumpkin. All of which you can get at the site above. You only need a few drops per batch so a couple onces will go along way. I also like Dels 2 piece aluminum stick mold. I just started pouing and have yet to pour a bad batch from it. As far as glitter goes, if you are making the three colors I mentioned above I would get green, red, and black. worm oil is used to keep the plastic from sticking to each other, so I highly suggest it. I usually put a few drops in the plastic bag and spread it around. Then I will add the worms and put a few more drops on them and mix the worms around in the bag.
I hope this helps.