Spitting oil through tailpipes.

Are you sure the header evacs are 100% disconnected?

If they are disconnected, then why not expect this as normal? You have no crankcase evacuation at all anymore, and the crankcase pressure is going to push oil somewhere. If it was OK for oil consumption with the evacs in place, then disconnecting them is like disconnecting a a PCV.

As for oiling restrictions helping, I would not be surprised. It's gotta be pushing a lot of oil into the exhaust for it to not be all burned and for the plugs to look so clean, so pooling, with the crankcase pressure resulting from no evacuation, seems likely. Or a restricted drain back to the pan. Pulling a header would be next on my list, as suggested by others; if it is excess oil pooling in the heads, then I would expect to see more oil residue in the back header tubes.