You are correct.I was thinking that I would need to cut an opening on the opposite side of the stand to where the fan is to get cross ventilation. It seems like having an opening right above the fan would just pull the air from above itself and not grab the rest of the air in the stand.
It sounds like it is working for you though. Any issues with moisture?
I have some openings in the front of the stand however the guy who built my stand left a big opening for a center rear overflow.
I do notice the fan helps, especially here in NY where we keep windows closed during cold months and co2 is high in the house. I got a kalk stirrer to fight that.
Moisture also is reduced with it so it is a big helper in ny opinion. I dont get any condensation compared to other systems I've had.