Mark,
What I do for the LBZ guys (and most others) is my Kennedy Custom tuning. I send out the ECM with the tune installed and the customer either purchases the core ECM or returns their stocker. In your case I could use your second ECM. Swap is simple.

I have a very nice 70HP Perf/Tow tune for the LBZ that would suit you well. Smoother and stringer than other commercialy available tuners that claim higher HP numbers.