If you go on Summits website you can use their filters to cherry pick what you want in oil.
For instance you can select full synthetic, 5w-20, ZDDP enhanced and come up with several
brands of oils that should work well in a splash oiled air cooled engine.
I've used Joe Gibbs Racings "Driven" brand and the Brad Penn "Penngrade" oils in my automotive
race engines and like both.
I'm doing a mobility trike for myself for outdoor event usage, which will use a Tillotson Wildcat 223
for power. I pulled this engine down and made sure all the wear areas had lube before first start.
I used a 30w ZDDP enhanced break in oil for a few low throttle heat cycles, then I pulled it down for
inspection. Removed governor, including drive gear from crank. Installed 22lb valve springs, .010
head gasket, head studs, new coil, (factory ones are limited to 4K RPM's) and a timing key. Another
couple heat cycles with the 30w, then I will drain and fill with whatever premium brand synthetic
5w20 ZDDP enhanced oil that I can obtain locally.