Favorit brake servo output rod adjustment

The replacement non-OE servo I have bought has an adjustable output rod, whereas the original does not. The one I have appears to be based on the pre-93 one which was adjustable, (but should work on my model).

The Haynes manual states there should be a clearance of between 0.3 and 0.6mm and to measure a variety of things and add and subtract. The problem I am experiencing is that my measures seem to vary greatly each time I take a measure with a digital micrometer, no matter how careful I am, so getting a clearance in the range of 0.3mm is impossible.

I am just wondering if a more common sense approach would be to adjust until resistance is felt, and then back off slightly until there is no resistance when placing MC on servo? and wanted to check whether this approach would make the brakes operate safely.