A good practice in making wood from deteriorated wood pieces or totally missing wood, is to make paper patterns from the sheet metal, then make trial pieces from scrap wood, fitting them to the sheet metal, assemble with screws/clamps/rope and check the fit of the metal and wood parts. Make adjustments or note the changes to be made. Only then do you make the final wood pieces out of more expensive wood. It likely will need some final fitting but much less than if you try to make the final parts the first time.