Rogue what you say is logical and I agree. But I'm not a lub oil expert and since I have found that Castrol and Valvoline are competitively pricerd I am making inquiries about them.
Shell Nautilous is same as Quick Silver. Shell produce it and they sell it on to Merc. I also think Valvoline is the same oil but I'm not sure is just rumors that I've heard, the same applies for Castrol.
QuickSilver and Yama lub and also Nautilous are quite expenssive I think Yama Lub is the dearest.
So still asking if any one knows whether the specs of the Valvoline and Castrol are the same as of that of Quicksilver (That I may add we used all summer and our pockets are dry