Another key factor for release, and VERY CRITICAL, is making sure the wooden mold is lined properly. GoPlanetEarth has put together a video tutorial (see below) showing the method we use to line a wooden loaf mold. It has proven to work well for us and we've experienced no leakage around the base of mold.
If you are still concerned about leakage issues after lining mold, I suggest purchasing dental wax and push into the areas you think could be problematic. Dental wax is very pliable and easy to remove and reuse. You don't want an overkill with the wax. It could impede removing the top portion of the mold from the base and you won't be able to remove your soap.