You obviously have a fudimental problem with your timing mark or light. If you have 60* initial and an aditional say 24* mechanical advance there is no way it could run with 84* advance unless you were using candle wax for fuel.
"There is 45* distributor rotation between cylinders so the rotor should be almost to the #8 plug."
The rotor should be pointed right at or just after #1 terminal on cap at TDC.
If you rotate the engine to say 12* before TDC, the rotor should be pointed directly at the #1 terminal if your using close to stock advance.
Any chance the balancer ring has rotated on its hub(happens all the time).
Any chance that when you used a piston stop that the engine got stuck in its rotation before the piston hit the stop in either foward or reverse rotation making you think it hit the stop(stopping in its foward rotation would result in an over advanced "zero" indication if I'm not mistaken). Did you unscrew the stop a little and see if the you got the same results?
Any chance that you put your mark on the opposite side of the balancer between the two marks? If you had the piston stop screwed in to far it could be an easy mistake. I really think you should try the piston stop method of finding your TDC mark again! I know your certain thats not the problem, and thats where your having so much diffuculty. I agree that its probably not 3 different lights, although I've had severe problems with a dial back light on my MSD 8365 HEI.
I was an electronic technician for over 20 years, and one of the 1st things I learned about troubleshooting a problem for someone else is not to take their word for a diagnostic step they found to be ok as that was often incorrect and the reason they couldn't fix the problem.