[BRENT in 10-uh-C]

First question, are the spark plugs in order from #1 (L) - #4 (R)?

My initial observation is oil is possibly coming from the valves. The fuel mixture appears to be close based on spark plug tips. The carbon appears to following the suite of the combustion chamber which would indicate to me that it is originating from valve guide area and not piston ring. Typically you see more even spread of carbon around the entire piston top when it is the oil rings that are worn.

To totally diagnose this, it would be better to see the margin of the valves, the seat surface, check concentricity, and valve stem to guide clearance. I would also like to measure the bore with a feeler gauge to see how loose the piston is in the bore, etc.