Sorry I didn't get back sooner, life got in the way.
Saturday turned out fantastic, the pork was so juicy & tender, and everyone had a great time.
What surprised me was that the pig was done sooner than we expected. We ended up having to keep it warm in the oven for about an hour and a half. Alas at that point we lost all the nice crispy skin, as it got a bit soft.
As for the pig roaster... my friend borrowed it from a friend of his, who made it at home. I don't have all the details, but it looks fairly simple. There's the bottom which is made from square steel tubing with a sheet of steel on top.
Then another frame of steel tubing with steel sheet that has the bearing bolted on. Opposite side has the motor assembly. There's a back that just clips on, and a top that just sits there to help hold the heat in.
I'm not sure but I think it is a 2 speed furnace motor with a gear reduction so that the spit speed is either 4 or 6 rpm depending on which way the switch is thrown.
The charcoal tray is a separate piece that is raised off the bottom using a couple of patio stones. This way there is an air gap between the charcoal tray and the roaster, and a gap between the roaster and the ground.
Apparently, you could use this on your lawn and not worry about burning the grass.
If anyone is interested, I'll try and get more details & photos about the roaster.
Unfortunately, I didn't get any pictures of the pig once it was cut up as things got busy.