: Mike-
: Another approach to this problem (you are not far from dead flat @
: 1/16") is (starting with a clean deck and hatch rim) to put
: a few (fingernail-size) shims on the deck to hold the hatch rim
: flat. (Glue the shims in place on the deck-make sure they will
: be covered completely with your sealant/adhesive).
: You can even glue the shims in place and then sand flat with a
: piece of (flat) plywood with sandpaper attached.
: Apply sealant/adhesive and bolt/screw/weight the hatch rim in place
: with minimal pressure. The shims will keep the hatch rim from
: flexing. Clean up excess adhesive.
: Let the adhesive/sealant cure well (days to weeks, depending on the
: goop) then tighten up the fasteners.

Beckson recommends a good 1/16" thick bed of sealant between the deck plate and the deck. As long as you don't wrench on the bolts you should be able to use your existing setup as is.