OK, so I believe I have it working now, at least in my test case so far.
I actually can still program Live with normal MIDI notes (all full velocity 127), which makes it easy to drag them around the sequencer timeline to sync properly. I obviously have to match the notes I program with the existing setup for the BCF2000. E.g.
G#5 is 92, set to tap tempo,
C#4 is 73, set to next (Go) submaster 1.
The shift function took a bit, but it's fairly obvious (it just didn't work consistently for me, so I thought I was doing it wrong).
F#5 is 90, which is shift
I can program two notes at once, with shift (F#5) starting before and ending after the other note, e.g. C#4 (73) is my "blackout group 1".
This works.
See the screenshot if you're interested. This shows two tempo taps, then a blackout, then a submaster go, then start, then blackout (back on).
AbeltonLights1.png
Fades/knobs (not buttons) can be done using the envelope, as in this screenshot, showing CC 2 (submaster 2 speed) being set. You have to find where 100% is (25 here) first.
AbeltonLightsEnvelope.png
If anyone is actually interested, let me know and I can write up a wiki page on this.
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