In normal case of slitting knife clearance is 10% of the material thickness, e.g. if the material is 0.3mm in thickness, the knife clearance is 0.3mmx10%=0.03mm.

In order to get proper clearance, you need to have special spacer 1.94mm.

Below are some examples for your combination reference.

1. To get slit width 23mm: (needs special spacer 1.94mm)
   10(knife)*2+0.03(clearance)*2+1.94(spacer)+1.0(spacer)=23mm 
2. To get slitting width 23.1mm:
   10(knife)*2+0.03(clearance)*2+1.94+1.1 (spacer)=23.1mm
3. To get slitting width 24mm:
   10(knife)*2+0.03(clearance)*2+1.94+2 (spacer)=24mm