Re: Motor running faithfully now, but.......
Good to hear that it sounds like you've got it figured out. Your description of running rough sounded familiar to me, even though our motors are probably very different.
I've got a homemade friction drive rig with a Homelite 25cc two stroke. Normal operation for me is to put it on full choke when I am starting it completely cold (first ride of the day). I have a 3-position choke. Full choke is only for a second when I first engage it, and I might have to "play" with the choke between full and half for a few seconds until I get up to a cruising speed. I'll leave it on half choke until it heats up (maybe a minute, depending on weather) and I can hear/feel when it is ready to flip to no-choke. Then she runs great as long as she's hot.
But I've found out that this little engine is sensitive to the temperature. If the temp is below 40, I have to adjust one of my carb mixture screws a little (there's two screws on mine). If its over 70, I'll adjust it back. No big deal, once I figured that out. If it's not adjusted, it acts just like there is not enough/too much choke and runs just like you described.