Design Change to the Passive Solar Window Box Heater

I have been using a 4 solar fans to push the warm air back into the room.

I now think, using two solar fans will do the same job.

I currently have 4 openings, which may decrease the heat build up.
Reducing the top four openings to 2, could get my inside box heat to higher then the current 96f.

I plan to incorporate these changes over the weekend

Dave