[Schulisco]

Definitely check the mixture with a lambda tool, both cold and warm. Guessing it's still too rich. The CDI generates such a strong ignition spark to ignite a rich mixture as well. (This is one of benefits why Porsche introduced the CDI). How is the idle CO adjusted? (factory setting was 3,5-4% or carburetted 911T).
Does your distributor work properly? Check out if the advance works correct as given by from factory, especially for the lower rpms before start (almost 0° adv on start, up to 35-40° on 6000rpms on carburetted engines, depending on yours and the mixture (the richer, the more advance and vice versa) and the fuel; 40° is pretty high! Be aware of damage!
Are you sure that the PMO's won't run empty while sitting? It's a common problem on some carburetted Porsche or beetle engines after sitting a (longer) while that the carbs run empty and the fuel pump requires some time to refill the carbs while cranking. Does the engine starts the second time better? If so you can add a second fuel pump parallel to the normal one operated by a push button on the dash to refill the carbs quicker.

Originally Posted by Mr.P 911T 1970

Feels like I need more (hotter longer) spark...

It was suggested that I switch my ignition coil from the Bosch to MSD. Is the original Bosch CDI compatible with the MSD coil? Blaster Series? High Vibration? Which one?

Have a look on this page: https://www.911-hkz.de/Zuendspulen.htm (automatically translated by Google translator) Check out the full text, below there's more about the MSDs.

Thomas