i experimented with vegetable glycerin, propylene glycol, and polyethylene glycol.
i also experimented with different forms of hash, and found that qwiso works best. dry ice or dry sift isn't a good choice. they don't dissolve well in any of the choices.
i just bought a bottle of pre-made Wax-Liquidizer, and i like it. it's made from polyethylene glycol 200 and 400, which refers to it's specific density.
vegetable glycerin doesn't dissolve anything well, propylene glycol isn't a lot better. i got a bottle of peg-200, and that was much better than both, but it would still separate eventually, if i let it sit around long enough.
the Wax-Liquidizer has 200 and 400, which apparently helps it stay in suspension and not separate.
i'm pretty sure i can duplicate it, but i have to get a bottle of 400 to play with first, then experiment with ratios. i'll let you know how it goes if you remind me, i don't have a memory to be bad