I normally want my soap to gel because of the brighter colors, so I force gel on everything but soaps with sugar (including milk soaps). Soaps with sugar (honey or milk) I put in the fridge after pouring for a few hours to explicitly prevent gel.
I force gel by putting my molds into a large cardboard box that sits on top of a heating pad. One side of the box is cut away/open so I can slide in the molds. Then I have a blanket that goes over the cardboard box to insulate the whole thing. I click on the heating pad medium which auto shuts off in two hours.
I've never had a soap not gel, so I don't know why I'm so uptight about always "putting it to bed" in that contraption. It would probably be easier to cover the top with a piece of cardboard then cover with a towel. I have done that and the soap has always gelled. If I ever have to move my little insulation box set-up, I'll probably just go with the cardboard on top to protect the soap + a towel...
Oh wait - now I remember. The reason I set up the cardboard box in the first place was to force gel on single bar molds. Not just because I'm crazy, which I am.