First off you're assuming traditional comics audience. If Mark says go buy this, his legions do so.
Second, we were assuming all sold through diamond. Remember that they have their own store front. If they sell through it, it isn't 60% off so that's higher than what is calculated.
Third Benny said he was primarily meeting with someone about Markiplier comic sales in LA.
So there is a dark horse in this race.
I am betting that we see record sales on Markiplier #1 easy.