So first - rewire the fronts. I could only get so far before pulling the cable through the belly and up into the electrical access meant I could pull no further, so there I tapped into the factory run 12ga for the final 3 feet through the wall itself.
Since you went to the original 12 ga wire anyway, you might have well run 12 ga all the way. If you put a fuse on those front jacks greater than 20a you will now turn that 12ga section of wire into a fuse that is inside your walls. Your circuit is just like a chain, it is only as strong as it's weakest link.
Dave
