I don't use the oven to force gel. Too many horror stories of overheating, volcanoes and melting molds.
I use the trick that I learned at an Otion (Brambleberry's retail store in Bellingham, WA) basic CP soap making class - I put the mold in a cardboard box that sits on top of a heating pad on low. The box is open on one side so you can put your molds in / out but covered with a blanket to insulate the box & close up the open side.
I turn on the heating pad to low as I'm making my soap batch. It automatically turns off after two hours. After the soap is ready, I place the mold inside and pull the blanket down to cover the opening. Next day, pull it out nice & gelled to cut.
You can place your individual molds in this also. When I do that, I put the heating pad on medium or high to help the gel process along more with smaller volume molds. The box I use is a "Medium" Lowe's packing box which is pretty big (18"x18"x16"). The nice thing about that is that you can fit bigger molds like the BB column mold inside it also. I actually put the column molds in here too on low. Never had them volcano and the gelling helps with getting the soap out.
It's like a handmade Easy Bake Oven for soap makers.