How to win with Face-Down-Cards

Hi,

I m trying to build a deck heavily around the manifest (dread) mechanic - as i saw the Jumpscare precon and liked it. Yet I only play commanders from outside the magic universe, so i will be playing [[Mike the Dungeon Master]] together with [[Eleven the Mage]].

First i like the whole horror stuff being thematical with StrangerThings and secondly i think that Mike has a little synergy with this, as he can revive a killed manifest on its front side. El only provides access to blue (and lets me play [[Kaust]]). So it will still mostly be simic.

the real question is which is the better way to build around manifest dread: Relying on

Turning cards face-up OR Flickering them for strong ETBs

?

As for the first i rather need strong attack triggers or flipeffects while for the second i need strong ETB effects...

Which do you think is better? Also I m open to card suggestions for this (apart from cards already in the Kaust or Zimone precon)

THX