sometimes it is hard to get a true read on the plugs these days. the gas nowadays makes it harder. If it were me, I would use a cheap O2 gauge to get a better idea. Even if you just use a narrow band, that would give you a good idea especially if you are running lean. The way you describe it, it would seem like you have richened it up to the point where it is either spot on or ever so slightly lean. Of course cliff has recommendations in his book for setting up the jetting/rods and the bleeds. If it "surges" at all while at a steady cruise (no enrichment by the rods due to high vac signal) then it will need just a bit more. Usually, the needle needs to somewhat match the jet but there is a window as far as the size goes but if I remember it needs to be in the .030-.035 range smaller than the jet. (its in the book) If you go too far, then the bleeds MIGHT need to be made larger too. I am sure Ethan has the specs for the carb that came on that engine, (hint hint). Those would be nice to know also.