All edible inks aren't made equally. I highly recommend icingimages for ink (gold label inks) and frosting sheets (premium sheets). I've used several brands and theirs are the best in my opinion.
You can also roll it out between 2 sheets of parchment paper. It won't stick as long as you release the parchment every once in awhile on both sides (just keep flipping it over and rolling from both sides).
Are you heating the chocolate clay or warming it with your hands before working with it? You should be able to knead it with your hands to make it pliable enough to use.
The cake safe spray booth is very nice but also very expensive. For a professional the cake safe booth might be in the budget for a hobby bake Earlene's booth can be built rather inexpensivly...
Earlene has instructions on her site to build a folding air brush booth. It folds for storage so it doesn't take up a lot of room. Google Earlene Moore and check it out.
I would stay away from glitter paper as the glitter tends to flake off and get everywhere inside the machine. I also use the premium frosting sheets from icingimages and have great success.
