I'm going to be attaching some wood fittings on my hatch covers to act as pressure points for my hold-down straps (ala Pygmy's instructions), but I've already varnished the boat - 6 coats so far. Should I sand down thru the varnish, then use thickened epoxy to attach those wood fittings? Or would using some Marine Goop (contact cement) to the varnished finish work okay?

any advice is much appreciated.