Hi Carl,
The VB is a great big relaxed lump that will run on anything. I rode one of them to England more years ago than I care to admit to.It had some awful smelling stuff poured into its tank on the way and it made no difference at all. It was designed long before lead was ever added to petrol and couldn't give a darn now it's been taken out again.
Same thing applies to oil. I used 50 grade in the Aust summer and 40 in winter. Whatever brand you use is going to be fancier than what was around when the bike was new so brand doesn't really matter. As there is no oil filtration system to speak of the only thing to be enthusiastic about is regular oil changes. Oil is much, much cheaper than a new engine. heers, Bob