We are going to enclose portions of underneath our house with slats beginning with this section in front of little shed, another section to the right, and another to the left creating a little room under for shed, mower etc. There will also be a staircase down from the deck, and the slat wall will mean we only have to have balustrading on the outside. We are undecided what size slats would look best to compliment the balustrade already there. Should we go 90 wide ( verticle slats) with a 40ml gap. Or 60 wide with a 40 ml gap. The balustrade is 60 with an 80ml gap, but that is too open for this application.We need a gap for airflow. Should we also leave 100ml top and bottom ?