Blacklab, the thing folks try to do that throws them off, is trying to add too much heat at a time.
You can use either charcoal or hot coals....which ever you like, but make sure you do not add too many at one time.
People think the pig is not cooking fast enough or it will not be ready in time....You really need to go low and slow and make sure you put the heat under the hams and shoulders.
If you get the hot coals off to one side....more of them under one ham than the other, one side will be cooked sooner....it's a good idea to place the heat as close to the middle of each end as possible.
Hope you have good luck with it.
edited to add.......I've never had one take more than 9 to 10 hrs....most take around 8.