Rob, I can take care of the early trigger point. What I have experimented with was to set my low rpm timing to zero degrees and the total advance to only 17 degrees for top rpm. It works that way and I don't have to really move the hall mount much.
When I ran the engine that way, it still started easily and gives me the same top rpm and power as before.
The oscillation I was getting at slow speeds was fixed mostly by adding the .1 cap on the hall leads. It only does it now at starting speeds and then goes away. One odd thing though was that it takes 2 passes with the magnet after power up to produce the first spark. Charlie mentioned that also in his testing..kind of like it tests the speed first to make sure the engine is rotating or something..not sure what it does there.

John