Yeah, VR1 is all this side-oiler has had in it. But over time, I've worried more about the 20W-50 during start-ups, and the fact that it takes a long time for the
oil to get up to temperature. I wish there were a lighter viscosity VR1 multigrade.
I think Jerry was on to something with many of us running
oil coolers, remote filters, etc. Most of us are rarely driving in the types of conditions where those things are required.