If you know the valves are good then I would check the timing belt tension as I suggested in the last comment. I do believe I did mention to put a little sealant on the corners of the valve cover gasket at the arches in my video as that is actually Honda service procedure, you can reuse the gasket as long as it’s still pliable and not hard and brittle. I don’t recommend anti-sieze on the plug threads, just a drop of oil is much better in my opinion but it’s not going to hurt anything. Here is a link to my ‘power balance’ video.
http://www.youtube.com/watch?v=bAOmUjAjNjE
If you do it for a prolonged period of time it might set a CEL but if it does you can just clear it and ignore it. I would be checking the belt tension first however.