If the access issue is due to a fiberglass liner, then it's a fairly easy process.
Home deport sells chromed metal plugs that can be inserted into the appropriately sized holes. Drill a hole, through the liner, big enough for the backing washer and through bolt your clutch to the deck. Insert a plug an you're done. An additional step I did was to paint the plugs (sand the shine off and spray with a rattle can) to match the color of the liner and they are quite inconspicuous.
Cheers
Matt