Thanks for the in-depth responses everyone. The mulligan is an important factor I have overlooked. I was playing Crucible of Worlds and a bunch of fetch-lands to go with that. As a result, I usually shuffled my library before activating Grenzo. Cutting that package now. I play with a very stable pod...

I'm not entirely convinced that the deck doesn't need to draw more cards. Here's why: More cards means more lands. Only about 5.5 out of 15 cards are lands. That's not very many by turn 8. Because we can't ramp as well as others and Grenzo is very mana-hungry, consistently playing lands seems import...

How do you feel about Yawgmoth, Thran Physician as a sac outlet?
It doesn't allow you to go infinite beause of the life payment, but killing mana dorks while drawing cards seems pretty good.
It also doubles as a discard outlet.