More like, I'm running 30 card decks with around 20 or so creatures in them. For fringe cases, it could go as low as 16 but that hasn't been the creature count for my self-mill decks. Also, a little over 60% of my Cube is creatures. So if you used Tapping at the window on my entire cube you'd still get around a 94% of hitting one creature.Wait are you sure?
I personally think 19 creatures in a 40 land deck is unrealistically optimistic, especially in the kind of deck that wants self mill think twice.
How many glasspool mimics and Shoreline scouts are in your cube that you can get more hits than that? Are you just running 14 land decks by default?
If I'm reading this right (and please tell me if I'm not), you need 27 creatures in your 40 card deck for a 97% chance to hit at least 1?
It doesn't follow almost any of the normal Cubing rules besides that you draft and then play a relatively normal game of Magic. You're pretty close with the glasspool mimic idea though, but I've been working on this Cube since before Zendikar Rising. That's all I'll say for now.