From Paulorenzo's mail....
"According to Denso, the auto-switch function will do 2 things:
- start the car with petrol (tried and tested)
- automatically switch to petrol, when LPG is empty (never tried this - I always fill up when the red "E" light starts flashing)

EROOM user here. Very satisfied customer."

That feature is what I want.

Niky, do I presume correctly that Speedlab with tune only the LPG side of the system?