So no go for plan B? Haha

Thanks for the responses. I wish somebody knew more about that $100 hat if it is a tuning nightmare I will steer clear. Going as big and tall as possible totally makes sense. The paper filter should slow down any air flow enough to prevent a lot of turbulence above the vents and butterflies- as long as it’s a big enough ‘filtered plenum’ it won’t get ugly and windy in there in a bad way?

My third idea came from the dollar store and is not the best one but for $6 worth a try for ABA testing...