"... but my primary suspicion is that there is too much oil spraying around the top of the head." The problem is not too much oil spraying around, but oil seeping into the combustion chambers. I'm not any sort of engine rebuilding expert, but I'd lay odds on valve stem seals - particularily the intake valves - as a likely source. Just my 2 pence worth!
What say you, Motorbill? Lay your words of LBC wisdom upon us mere mortals! 