I've done plenty of whole hogs, but it's been a while. What's your end goal? Are you rubbing or injecting? Just letting the sauce speak for it? I'm down in SC, and I don't inject or rub my whole hogs with anything except salt. Sometimes I'll stab the hams and loins and rub some salt down in there.
Also, most people start the hog open/meat side down, then flip. I've done it that way and I've also done the whole thing on its back/skin side the whole time. It just takes a little longer. And if I have help, I like starting meat side down to crisp and char up some of that outer meat. But if I'm doing one by myself and don't want to try and flip it by myself, I just go skin side down the whole time.
Obviously it's ready when your thermo says so. But an old trick some old salts taught me to look for is when that shoulder bone will turn around freely in the ham. When that bone is loose and spinning that's when I start probing with my thermo.
After that when it's done, I start pulling all the meat. Taking out the bones and crap you don't want. Be careful to try and not puncture the skin underneath. It'll act as a vessel to hold all the sauce and goodness in when you start saucing. I use a vinegar pepper sauce because that's what I was raised on and what I consider true whole hog barbecue. Once the meat is all pulled and shredded, start saucing it. Basically I start spooking sauce all over the meat and tossing it to coat. Then let it cook through some more on the pit. After a bit some of the sauce and fat will rise back to the top. I usually skim this fat off and keep saucing until it's how I want it.
That's the skinny on how I do mine. Enjoy!