Make sure the valves on #6 have some clearance. It's possible the #6 exhaust valve is still stuck a little, or there might not be enough clearance to let it close fully. For now, don't get concerned with exact clearances- - - -just make sure there's some slack in the rocker arm with the cylinder at the top of the compression stroke.
The longer you let the penetrating oil soak, the less likely you'll stick some valves on startup. Working the valves up and down with a pry bar on the rocker arms is a good idea, as long as you don't get rowdy and break a rocker! I've also been known to thump the top of a valve with a dead-blow hammer a few times to dislodge carbon deposits on the valves and/or stems.
Jerry
