That Moo bundle is good.
You can use halftone filters:
I don’t know how you’re setting your image up, a quickish way may be to mask the flat colour areas beneath your linework/ inking, add a new paint layer above your flats & shade with brush in there, then you can make a halftone filter so you have an editable screentone-like layer to adjust to your liking.
@Grum999 shows a good quick halftone demo here for reference: