Hi Bigskyrc: I have the same engine from Walker that I obtained from a good friend who bought it new direct. I had the throttle coupled advance and was a pretty bad shaker, enough to move the ring around with the hall effect. I decided to lock the ring down and add the electronic advance from C&H to the ignition package. This combo has not stopped the shaking but has reduced it significantly enough that I rate it as a non-issue. I am currently running the engine in a Byron Christen Eagle and it is a dynamite combo. It was living on a Giant Stinger and with a 20x8/14 would pull it verticale out of sight. I use Poulan synthetic oil mixed 40:1 and have had no overheating, idle, transition, etc issues.
Love the engine, you got a good one.