yet another mistake on my 360 build?

Lean burn distributors have no advance at all, no vacuum or mechanical and are usually dual pickups. The way this sytem worked was all the advance was dialed in with the intitial set, usually around 10 -16 degrees. The actual advance was about 60 degrees. The lean burn computer let the advance out as needed, in other words it just retarded the spark and let it out as it saw fit. The second pickup was for starting the engine as with 60 degrees advance a hot engine would not start very well.

Since you didn't provide much info about your combination and my crystal ball is still broken what you need for an advance curve is going to be a mystery.