Spark Plugs

couple questions about plugs.
got the ngks (zfr5n), gapped them to .040, pulled the washers off. seemed to run well. after about 300 miles i pulled them to see how they're holding up.
it looks like #1 is getting oil on it/burning oil. maybe bad valve seal, but it looks like there's oil on the plug threads. could oil be seeping past the drool tube into the threads?

also, i run about 9.0:1 compression. (head milled 0.090, bigger valves) should i be running colder plugs? all the others look good, nice and tan, no ash, no spots.