Retro is better
I use 30W dino oil without additives, about every 12,000 miles. Those new additives are actually detrimental for air-cooled engines, and the oil passes the heat better in the radiator without additives. Synthetics can corrode your aluminum and will start leaking from the resultant hairline cracks in your engine case.
And vinyl records sound better than CDs.
Seriously, I use Amsoil 20W50 motorcycle oil once a year, with a Purolator Pure One 14612 filter, whether it needs it or not.