I'm putting the finishing touches on my homemade cabinet style bator and I'm getting ready to put the fresh air vents in. Does anyone know approximatley what size vent openings there are in a Sportsman type bator? Also, how many openings and the locations. I'm thinking of two vents, both 2" with revolving flat covers to regulate air flow. Also, I'm thinking of locating them both on the back wall, one on top and one on bottom. Am I close in my thinking? Thanks in advance, Jim.