The problem with our small engines as opposed to the "big", two strokes, chain saws, dirt bikes and the like is that they use needle bearings on the connecting rod. The engines are big enough to accommodate the mass and bulk of such a rod. Our engines are too small for that so we have plain bushed connecting rods. As such, those need far more lubrication to prevent failure.

Cox rods are even worse in that respect. Standard, pin type pistons have two holes in them allowing for lubrication to get into that area. "Shrouded" rods as you find with Cox, some Fox and all VA engines have the piston end of the rod nestled deep within the piston. Not a lot of circulation of fresh fuel/lube gets in there, I'm afraid.

And that points out the superior lubrication qualities of Castor. Castor works in such a severe environment, synthetics don't. At least not yet. Downsides with Castor is that the oil has a higher viscosity and presents more drag. Especially in the cold. Plus, at very high temps, Castor caramelizes. That's just a nuisance of course, but that's in fact a good feature as it will prevent galling under severe conditions of overheating and/or starvation of lube at overlean settings.

In my former day job, we sold an EP (extreme pressure) additive that enhanced an oil's capacity to resist failure. This was demonstrated with a device that had continuous lube delivered to a bar rubbing against a rotating flywheel. You would add weights to the bar to deliver more and more pressure against the rubbing parts. Any standard oil would have the parts squeal while the treated oil would just run happily away. It was amazing, you could add triple the weight and still not get a failure. Apparently, all oil gets this additive and adding more made it better. I never did try the additive, for some reason. Wish I knew now what it was. As I recall, it was quite expensive.