Glad its fun to watch. Thats part of the reason I made it. Also, the video doesn't do it justice, its really the most pleasant air compressor I've ever been around partly to the nice pump, but a lot to do with the engine noise as well.
As far as belt wear, most of the belt is guided away from the moving pulley when its slack. There are guide pegs around to help the belt maintain a favorable shape when it is loose. There is sometimes some contact on the top edge of the pulley, but the belts are kind of floating there being held up by their natural shape, so any contact is minimal. If I notice that it is a problem, I could probably help it stay off the top of the pulley with a hook on the idler arm placed so that it guides up the belts just a hair more when the arm is fully raised. There are also some adjustments in the guide pegs that could get the belts moved into a little better position with some tinkering with the adjustments. I don't have enough run time on it to tell if wear is going to be a problem. I have not noticed any heating or signs of damage to the belts as of yet.
Yes, the cam oiling seemed like an excellent idea, and was pretty straightforward to implement with your instructions. I suspect the governor does not like my linkage tightening springs, they are probably too stiff. I'm chasing down some alternatives that should get the job done with less force. A longer spring down on the adjustment arm would also help, the short one it came with rapidly decreases its force as the rack nears full open, and thus it isn't as able to overcome the slight spring pressure from the linkage slop springs anymore. Its too bad that the hardware store here seems to have a large rack of all types of empty slots for springs and never seems to have any of the smaller ones in stock. I could size up something close by feel, but a list of specs to order one might be a shot in the dark. I'll see about venturing to a few other stores sometime this week.
I also found and corrected an intermittent binding on the far side arm under the pump. It was allowing the lever under the pump to get too far to the side and that would cause binding if everything was in the right spot, but not all the time so it was hard to find and I had missed it when I initially went through the linkages. I suspect it was able to bind more often when the engine was in operation than it did when it was shut down. A further de-burr of the pivot and the addition of a thin washer as a spacer cured it. Although this helped the laziness, it was not a cure.