In practice, it's even simpler than the instructions says...

First note there are two CC systems, the US and European scales, the US in on USA made heads, and other on Euro makes... They do the same things, but different scales...

On a US head pretty easy as about 20cc M usually is about grade 2 1/2, 40cc M is about grade 3, 60cc M is about grade 3 1/2, 80cc M about 4 etc... To reduce contrast, 15 or 20 cc Y is 1 1/2, 40cc Y is grade 1... You find it is not rocket science as your test strip might need a little more or less contrast, so you just turn the knob a little to correct... But with good negs, you will print at the same setting most of the time, only changing settings to fix printing with issues (like thin or overexposed negs etc)... Take notes when this happens so you know what to do if it happens again...

The corrections listed on Ilford and other paper data sheets are really overkill and not needed to blend 2 colors to get contrast effects (if you looked at a MG filter set, you notice the colors are single of different densities)...

If you buy a colorhead, DO NOT buy one that uses an electronic interface to control settings, as most all get troublesome sooner or later, get one with a knob and dial that directly moves the filters as these are more reliable... All heads have filter stacks that can get stuck or be not repeatable if not lubed or serviced correctly, as these can have many hearing/cooling cycles over time than can eventually cause them to stick... The use of standard MG filters don't suffer from this, and are fine for most all single grade printing...

Enjoy the ride, and don't overthink/worry about it too much, it's easier than you think with a little practice printing...

Steve K