My books are in my truck, and I am just to lazy to go get them right now, but I would get the stuff out of there ASAP. The 75-90 is way to heavy. Not to mention that they might not be compatible.
I know that there are folks using all different kinds of lube sucessfully, but not 75-90 that I recall seeing. The specified lube is very expensive and I would use it if you are still under warranty. I never reccomend to mix lubricants due to possible additive package incompatibility.