Oil + additive viscosity

Do not use additives that worked in previous oil standards with SN OIL
WTF is "oil stabilizer" anyway I only stabilize my horses
and yes you could check how it flows at 100 degrees
but best advice is to let the oil companies do the blending
I'm using 0w-40 eruo spec in most everything- the MBENZ - BMWspec stuff except the VW Diesel which takes a low sap oil for the particulate filter (VW 507)
there are good xx-50 and xx-60 oils available but you must have the proper clerances