Hey @fredguile, good to see you again!
Maybe the video in this topic might be of interest to you:
Essentially, i use one of the engines as a MIDI Engine to send MIDI to the external sequencer to build things.
This allows you to use atleast 2 engines for pad mapping and then the last one that you use as a MIDI Engine you can at the end change to whatever you want once you are done with the first two engines.
Let me know if this helps or if you want to talk about best practices other ideas afterwards 
