Rubbed & seasoned under the skin with Simply Marvelous "Spicy Apple". Used the point of my Thermapen to perforate the skin so fat could drain more easily. (In theory, anyway) Had to use a thin, sharp knife to separate the skin from the meat. Not nearly as easy as with chicken... but worth it. Mixture of apple and cherry wood. 13" pizza stone on the "spider" for a heat deflector. Birds upside down to get the thighs up where the egg is hottest... and shield the brest meat a bit. Used a large oval foil pan to catch the drippings. Put an inch of water in the pan to keep the drippings from burning. Thought the steam from the water might keep the skin from crisping so planned to remove the pan and finish the cook direct.
When the temp reached 250° and was rising slowly... I took a nap. When I woke 2 hrs later, the temp had climbed to 350° (As I hoped it would), the birds were a beautiful copper color but covered with moisture from the steam. I took the birds out (balanced precariously on the deck railing) and removed the water pan and pizza stone deflector. Put the birds back in over the coals for two minutes. VOILA! Crispy skin. The Spicy Apple complimented the taste of the duck perfectly.
I think the water pan may have saved the cook during my nap... certainly didn't hurt it... Decided not to mess with keeping the duck fat after all.