I've used the acetone with epoxy 330, and use a small toaster oven for preheating the stone(s) and for curing once the mixture is applied. You could always hope for the best, and with a little steady pressure in the applying process you could work out some air pockets, before the curing. Always worked great whenever inlaying turquoise in labradorite.. but opals I wouldn't advise to heating.
While clearing out a house from the passing owners, I picked up a small medical vacuum pump and with a little rigging with a container, I managed to create a vacuum chamber. I haven't had the chance to use it much since it's creation, but the last few projects I did, it worked beyond amazing for removing all the air bubbles in epoxy 330 and opticon solutions. I mainly made it for stabilizing cobbles/slabs, but works well for inlaying and doublets. After the air is removed from said combination, you're free to remove it and cure it in whatever means from there on out.