I have a reverse flow (Lang clone) as well.
We've done a few in the 80#-100# range, keeping it at around the 350* mark and average about 6-8 hours (depending on weather, size, ect).
We generally do them racer style.
Foil the ears, nose and tail to keep them from getting too crispy.
Take the foil off about an hour before you think it's going to be done.
Put the hams on the hot end, for us that's the firebox side.
If you're going to put an apple in it's mouth, place a wood block (2x4 works) in it's mouth at the beginning of the cook. Otherwise you won't get the mouth open when it's done cooking.
If your cooker has a slide out rack and you're going to serve off the rack, that's fine. Otherwise, you'll want to cook the hog on something you can remove from the cooker. You won't be able to move the cooked hog without it falling apart (if you've done it right, anyway). A sheet of stainless steel expanded metal works well.
Let it rest for a good hour before you start to carve it. This not only redistributes the juices, but allows for it to cool a little. Even after an hour, you'll be burning your hands while you pull it. Plus, that hour allows people to "Ooooh & Ahhhhh" and take pictures of your awesome cooking skills. We tuck and overlap Romain lettuce leaves under the hog for presentation. It's only an extra couple bucks and a little extra time, but worth it. Remember: presentation is everything. Putting sunglasses and a lei (sp?) on the hog is nice touch too. This is when you put the apple in it's mouth, too, if you're going to do it.
To serve, use a serrated knife to cut through the skin - it'll be like boot leather. Cut the skin around the neck like a collar, then cut along the spine to the tail. Make cuts along the legs and most of the skin will come off. If you're serving the whole thing pulled, skin at all at once and do it all at once. Or, for Carolina pig pullin' party, I usually just skin half at a time and leave the other half with the skin on. This keeps half of the hog warm while the other half gets devoured. Just place a couple of tongs out and let 'em at it.
I'll try and get pics up later.
Hope this helps.
-scott