Today I set the timing via vacuum gauge. Now, it runs so much better and vacuum is holding steady in the green at 18. Now, there is no more hesitation and things have smoothed out. There was no pinging or flat spots. At this point, I am leaving my fitting on the modulator and have an appointment next week to have them diagnose. Transmission continues to work smoothly in every way with the exception of not shifting into 4th gear. I am not going to drive the car anymore until taking it to the shop. Going to be a slow drive. Sadly, I imagine that the transmission has to come out again but that's life.