I am planning a 30x60 or 40x60 pole barn depending on the size of loft I can build in it. 12 or 14 eve height, 4/12 pitch. I will be using steel trusses that are 18" in height. On one end will either be a 30x30 apartment in the 30x60 or a 20x40 in the 40x60. Looking for 9ft ceiling in lower. I...