the surfaces are hinged and pinned already as you stated-never had a problem on the hinges-as far as motor mount concerns-I used the mount supplied but I used a pitts muffler and redrilled the motor mount from its 45 position and mounted engine horizontal-I added the third line to the stock fuel tank and installed a fuel clunk on it to be able to defuel it-I did not let the manual trip me up after realizing they were given me a incorrect measurement on engine cowl-I just used a little modeling experience and put it together. not a bad model for the price