@Struja I bought a bucket of the proper spec lube for sunroof rails from local Tesla service depot in Canada.
It's a shop supply. They said they don't normally retail the stuff, but I bought it as just another part -- had them add it to my parts bill for a service repair job the car was in for and I was paying other things too... The service personal was able to slip me the lube that way. If the shop was down to their last bucket they may not have sold it to me.
It cost about $35 for what looks like a lifetime supply for a few Model S's.
p.s. it is a very light semi-translucent lube, looks white when applied to dark rails.
It is meant for plastic / metal interface lube applications, has a bit of "body" but not much, very soft and goopy.. I think by glopping itself along the rails it helps reapply itself with normal sunroof use.
If your lube has gone black and you see rails have gotten shiny bright (aluminum) instead of the painted black surface, and especially if rails are wearing along inside edges (sloping downward toward center of car)... the sunroof is near failure and an expensive treat to repair.
I would think twice about using any spray film type lubricant as a substitute for the real stuff.
