F... was able to follow your suggestion... but didn't have to look long before the spun pinion bushing was found.
Sorry it's been a few days since I checked the forum.
Between fork and knife (front and rear) rod. Also between the fork rod and flywheels. This is looking from where the cylinders were removed. Be careful, the oil will only flow for a very few degrees of engine rotation. Turn the engine very slowly with pressure applied. You will see pressure drop when the oil hole in the pinion aligns with the hole in the bushing. That's when you should see the oil.