Here's the operating spec of the cam adjustment.
Engine speed Position of camshaft Camshaft solenoid Effect on combustion:
< 2000 rpm - "retarded" - deenergized - Reducing residual gas quantities as a result of smaller valve overlap
> 2000 rpm and < 4000 rpm - "advanced" actuated - Reducing fresh gas losses
> 4000 rpm "retarded" - deenergized - Improving cylinder charge by means of boost effect
So from my understanding it's just acting like an on/off switch, so it would seem there's nothing to 'tune'?