Well, I am not sure how the real mustang system will work, and I don't know how different it is from a 360 to a 440, but when I was playing around with the painless system, and could not get my 5.9 to run with their base programming, I remembered people using the mustang systems before, so I slipped in the 5.0 tune program painless has for their perfect fit sytem and the car ran better.

Now granted, it I was running it on a different system. Not a MAF system at all. But the base timing and fuel tables worked pretty good for cold start and driving.
My only issues were the tables were a little lean, which the MAF should adjust for.
Spark was pretty good, but idle was a little low for my tastes.