Here in Kansas you can get a pig roasted at many small packing houses. I have eaten a lot of this at small country weddings around Wichita. They usually use a 200 lb. pig, and the meat is usually always very good. When you walk into the hall and see the whole pig laying on his tummy with a real apple in his mouth it is really impressive. They use huge cookers that will slow roast the pig and allow it to cook through without any trimming. And they even have huge drained carving boards that hold the whole pig. You should start slicing at the rear around the tail and slice the meat off of the hams first.
If you cook a pig on a spit over an open fire, then you have to trim off the meat as it gets done and continue to cook the inside meat that is not yet done. This is the technique that Greeks use on their easter lamb and vertical roasted Gyro meat.
If you do not have a big smoker to cook your pig on then you can always do a bed-spring hog. You get an old bed-spring. The kind that is made of steal and has the springs zig-zag from one side rail to the other rather than coiled springs. Then you dig a four foot whole the size of the bed-spring. build a fire in the whole and let it burn down to white hotcoals no thicker than 1 foot from the bottom of the hole. Rub themeat inside and out with your favorite rub and place it back side up on the bed-spring. The cavity will catch the smoke and let it flaforthe meat from the bottom up. Put the bed-spring over the hole with the fire and cover the whole thing with corregated cardboard. If the cardboard burns then you have the fire too hot or too close to the meat. The cardboard will also catch the smoke as the pig cooks. To tend the fire you pick up the whole bed-spring and set it aside while you add a few logs. If the fire is too hot then wet down some of the coals or elevate the springs on a few concrete blocks. Be careful if you do this because you might let too much oxygen get to the fire and make it too hot. If that happensthen close off the gaps with more cardboard. As an aternative to digging a pit you can stack up cinder blocks till you have a four foot tall firebox that will hold the bed-spring. this nethod allow you to leave a door for tending the fire. The secret is to keep the meat at least 3 feet above the fire.
If you use a pit like the Bandera then you will probably have to cut the pig into primal roasts and cook the pig that way. You could also get one of those wooden box cookers with the coals on the top. These cookers use small pigs but that should be enough to feed fourty people. I would love to get one of thes cookers and try it out.
Good luck with your pig.
