Hi,
Epoxy... uh no. I can only see that as a bigger problem.
I assume your problem is with the water jackets and not a compression leak issue.
On copper head gaskets with water jacketed blocks I use a thin film of silicone around each hole. By thin, I mean real paper thin. Put it on your finger and spread it around the hole, both sides. A lumpy job will actually make matters worse.
This might be a little old fashioned but I warm the engine up real well without water and then retorque the heads. Then let it cool down to room temp and recheck the torque. Then add water.
I also religiously use the Moroso Ceramic seal on water jacketed engines. Works well. Just follow the instructions to the letter.
For compression seal I oring the block and use a receiver groove in the head.
Hope this helps
Dave Koehler
www.koehlerinjection.com