rings seating in

[carboy]

well my engine is finally running good, but i have a problem with number 8 cyl. it was smoking real bad but after i changed the oil for the 1st time after 2 hrs running it's not smoking as much.
after my fresh rebuild and a trial and error on plug wire placement i'm finally running on all 8 cyl. i think that lots of fuel was getting into my oil from the 4 cyl that weren't firing before. when i changed the oil it was real thin and smelled of fuel.
my concern is that i hope i don't have to pull my engine and redo the rings on #8 cyl. when checking the plugs only #8 is black. i have 150 lbs on each cyl for compression. and now it still smokes a little after about 10 min of running , then when you give it the gas a little more comes out...anyone have an idea how long i should give it for the rings to settle in. i haven't cruised down the highway yet, i'm still 2 weeks away from that. i just run it for 20 min at a time in the driveway.