As Skellyman points out, the odds are that you're going to be better off with a modern oil. Now, if this stuff had really high levels of ZDDP or something like that, it might be great on some of the old, old stuff. But, I doubt it's going to have any more ZDDP than a modern PCMO.
On the other hand, even the average modern single cylinder motor isn't going to be all that picky about oil, even though the manual will tend to call for the latest specifications. If you were up here and concerned about price, I'd send you to WM for a 5 gallon pail of SN rated straight 30, and you'd be set.
I have a little story you would appreciate, given that you rebuild small engines. Around twenty years ago, I'm guessing, my dad and I had finished either seeding or harvesting at the farm, and we're about done getting everything put back. In the stereotypical farm graveyard of old cars and OPE, there was an ancient, small grain auger (guessing from the 1940s) that had been sitting there for at least twenty years. It was simply too short for modern grain trucks, much less modern grain bins.
He decided he wanted to get it going. I'm guessing it was a B&S, from what I remember of the design. Well, we pulled the plug and gave it a brushing. The gas tank came off for a cleaning. Fresh gas was dumped in, along with a fresh fill of QS 10w-30. A few pulls later, and it was running.
Let a modern single cylinder sit outside for 20+ years and see how that goes. Most people have more trouble with the small engines they use yearly.