As long as you can keep a close enough watch on it so that the paper towel isn't left to dry out, a gentle heat source will definitely speed things up for you. If you have access to the hot water heater or cover of your boiler/heat system, its a good place to use. Put them on a glass or china plate - a mug would work too - so that they get radiant heat thru the ceramic. If you put something over the paper towel (like a cup), it will slow the amount of evaporation of your moisture, but you still need to watch them and add some water if the paper towel starts to look too dry. As soon as you see any white from the taproots, you'll want to drop them into the soil asap. The longer you let that taproot get before you plant it, the easier it is to damage it. Fuck up the taproot, and you'll get diddly from them! In the future, a soak for six to twelve hours before you go into the paper towel will speed things up considerably as it softens up the hard outer shell of the seed and lets the taproot crack it easier.