Not sure on the actual vid ya mentioned m8 but on any artwork you can really use either way. If you plan an majority opaque piece it doesn't really matter if you go a little darker as you follow up opaque layers should cover most of the layout layer anyway, if your using lots of transparent overlay instead I would keep it quite light..As rick mentioned m8 its just a case of playing around a bit with your reductions..If your doing a full color piece your initial layout layer doesn't need to be done in black, personally i would use my lightest base color to do so but still reduce it a bit so my next layer can clean up any mistakes..GL