I just use a stick of bullet lube applied about every fifth cut. Works well but you do get a bit of lube build up on everything near by. Currently using a chunk of mixed lube melted out of several old lubesizers. I have no idea what's in it but it works well. Can't use it for bullets and I try to never let anything go to waste. Must be the Scots in me.
Most machine shop supply catalogs sell 2 inch slitting saw blades of various thickness and tooth count. I changed out the screw holding the blade to a socket head cap screw after struggling with the factory screw just once. Had to carve out a notch in the plastic for the head of the screw to clear. Now it is easy to change blades.
Thanks for the heads up on the belt. No problem yet with mine but it is one of the weak links in the system.
Bob