Erratic Timing

This is when you start thinking how nice it would be to have a distributor machine!

If it seems to like more intial, that's fine. We don't know the details of the cam or compression so we are just guessing. I was a little surprised it had kickback at 10*, now we know why. Glad you cleared it up!

I don't have an answer to the curve shape a 2000 - 2500.
Can you get the second spring to engage earlier by turning the perch?