i also user the Penrite oils, for the same reasons that Musky and Brian and others have mentioned.
HPR30, or Enduro.
I also suggest you don't use (any brand) oil that is older than 2 years.
After that period it will change (degrade), as the chemical composition changes, and the additives deplete / change.
This issue was confirmed for me by an industrial chemist from BP.
Therefore don't keep on hand, any more than you would usein say 12 - 18 months, and always use the oldest stock first.
And, let someone else bid on the 10 year old can of oil on Ebay!
Richard.