Cream soaps can get quite hot; you may not be able to prevent gel altogether. You could soap as cool as you can with the tallow and put it in the freezer for 1-2 days then the fridge for a couple, but I would do this only if you won't be upset if you get a partial gel. I've had cream soaps that I unmold out of the freezer and cut as soon as it's thawed enough, and the individual bars will still try to gel! If you go with gelling it, I would only lightly insulate, if at all, and watch it closely. Once it's clearly gelling, remove all insulation or if it appears to be going too fast, pop it in the fridge to prevent any separation. There are plenty of people here who use all goat milk or other milk products so hopefully they will pop on soon. I personally have found it's hard to prevent some heating of the soap in the mold with a lot of cream. Others may have better tricks than I.