Just my .02! I had and still have sometimes similar trouble. One thing I found is that sometimes no smoke can be from being too cold(too fat) I kept richening trying to get smoke but had no luck. I leaned it down just some trying to get my temp to around 200 then I started to get smoke and could make small tuning adjustments accordingly. I also highly recommend pre warming your engine, I fought tuning issues for a long time just from making adj when cool then changing as the engine warmed. Good luck and I fully understand your frustration with learning the tune. P.S. Check for air leaks too. Most of my engines have had leaks around the screw that holds the carb in, fixed those air leaks and idle was MUCH better.