I think the reason Jon says that triples will be touchy, is because you are exaggerating every single little control 'movement/adjustment' that the ECM does. The ECM PID ('closed loop') control of the factory CP3 was never designed to work properly with more than 1 CP3. We can kinda get away with it with 2 CP3's, but In order to smoothly control three CP3's, I would think it would be more ideal to "buffer" and "smooth/dampen" the signal to the 2nd and 3rd CP3's. Use the stock CP3 for the quick response, and then smoothly/progressively ramp in the 2nd and 3rd CP3's as needed...a "smart" controller if you will.
If I were making a triple CP3 controller, I would probably use the analog method for the 1st and 2nd CP3's, and then add an "as-needed" demand-based smart control for the 3rd one (a controller that looks at throttle %, rpm, and actual rail pressure, and then brings in the 3rd CP3 as needed)
JMO. Jon, correct me if im wrong.
Ben