Another vote for Memento Tuxedo black. I know GinaK is testing a black ink pad which will work with alcohol markers (Copics). It seems to be a richer dark black than memento.
I'm under the impression that you should not use Stazon or anything with embossing powder with Copics because it reacts with ink/nibs of the markers.
I sometimes get issues with smearing on a high humidity day. Those days I blast my paper with my heat tool. HTH.