As probably most of combination machine user I knew disappointment with planer knife adjustments. One time everything went well and the following replacement looked like a nightmare asking me for my lack of skill or cursing the manufacturer and eventually wondering what could be the right combination : cutter paralleling the planer-thicknesser bed or the planer-jointer outfeed table ? but this is another story and that paper aims quick or efficient or else accurate ways of replacing knives on the planer head.
The bellow drawing shows the quickest way of replacing knives with two magnet jigs fitting the head diameter that perfectly adjust parallelism between cutter and cylindrical head. The three knives can be removed then locked in a couple of minutes without any mishap. I get a gap of about a third a millimetre (1/64 ") between the left and right side of the 300 mm (12 ") planer-thicknesser bed and no more with the outfeed table of the planer-jointer. Pretty good for me.

The manufacturer templates that came with the machine led to satisfying and efficient outcome but demanded much time and care. The way they work is detailed into the user manual.

Accuracy may be checked but also knives adjusted with the following trick. An aluminium tube put on the outfeed table previously slightly lowered helps for precise control merely by hearing the noise difference between left and right side of the cutter head. Machine stopped I just have to rotate the cutter head by hand and counter clockwise so that preserving the sharpening.