Yup, I think I got it now... and it's almost done. One question though, was it ok for me to use window screen material, or are the holes too small for the mites to fall through?
Window screen is fine if all you're after is ventilation. If you want to use the SBB for sifting mites #7 or #8 hardware cloth is best. #1 hardware cloth is 1 square per inch vertically, #2 is 2 squares per inch or 1/2 inch, #4 is 4 squares per inch or 1/4 inch...etc.