Using your photo as a reference, see the shims on the drive side of the cover? KTM recommends those to be 1.00mm thick to establish rocker arm position.
Then you fill the gap on the spark plug side with shims to obtain an end clearance of 0.20mm to 0.030mm.
Shims are available in 0.015, 0.030, 0.050 and 1.00mm.
So... how's tricks?