The 23 degrees you are seeing is not initial timing. The way you have it now is the initial timing advance is 14 degrees (7 degrees on the crank x 2) with an additional 9 degrees of centrifugal advance by 1200 RPM and an additional 17 degrees of centrifugal advance by 2000 RPM for a total timing advance of 40 degrees.
It seems to me the centrifugal timing advance needs to be limited 5 degrees with bushings under the weight plate (or however MSD does it) and the initial advance raised from 7 degrees to 12 degrees on the crank. About the only way you can set the initial advance if the engine will not idle below 1200 RPM is by increasing the initial advance until the engine is difficult to start and then back it down.. Initial timing 12 degrees "on the crank" (12 x 2 ) = 24 degrees initial advance + 12 degrees centrifugal advance = 36 degrees total advance. After the initial advance is increased to 12 degrees on the crank, you must readjust the engine idle to 1200 RPM.
You cannot observe the initial timing advance with a timing light when the engine is idling at 1200 RPM.