After a rebuild and gentlemanly low-rpm running tests of my MK1 I am a bit perturbed about oily plugs and pools of oil that form on the tops of the dished pistons. I have used Otto gaskets, with carefully added gasket goo around the pushrod tunnels, upper and lower surfaces. I have followed the initial torqueing down procedure for the head studs. My valve guide bores are unworn, and none of them loose. There's no significant exhaust smoke (yet). Cylinder bores and pistons were considered acceptable. There's a little oil coming out of the bottom engine breather tube. I see no problem with oil pump scavengeing, and being the plunger type I see wet-sumping as unlikely.
If the oil level in the crankcase sump is too high, for whatever reason, can it be that too much oil is being whipped up by the flywheels and sloshing up underneath the pistons, causing too much lubrication of the cylinder walls, leading to piston-top puddles ?