[mrnickleye]

You should never use JB Weld, period.

Those oil plug gasket by themselves will work if you don't replace the #3 gasket. I've seen that most of the time the oil in the spark plug holes comes from the intake or exhaust cam cover gaskets.

You need to put a little silicone gasket sealer on the corners up front. And put silicone on the front camshaft caps corners where the seals go. That's why you have the continued oil leaks on the timing belt back cover.