The airbox snorkel is removed and top opened up.
After much experimenting, including initially making up my own needle from and old FCR needle I had lying about, I got a Dynojet kit from Procycle.
Much more experimenting, and this is where I'm at:
FS 0.875 turns
DJ needle 4th clip from bottom
Leaner than most, but now working well with no surging and good economy, and pretty clean roll on from a closed throttle. Still no FCR, but thats coming, my Berg benchmark is a problem