I've just had my first ride after tightening up my spark calculation. It was a short ride, 10k around the suburb, not too much idling.
However I didn't notice any misses. So spark timing may well be the culprit.
I can tighten it up a little more but I was seeing some missed events so I need to fix some bugs to go any further.
BTW a lot of my round town cruising is at 2500rpm with no problems. Nice ad relaxing engine speed.
Anyway I'm off to work on a Saturday and the weather at the moment is great