The ceiling joists in our garage are 2x4's and I would like to get rid of them and raise the ceiling using 2x8's as rafter ties for our conversion. I know about the 1/3 rule when installing ties. The rafters currently (2x6) span 12 feet from top plate to ridge board. I would like to have the 2x8 rafter ties at the 4 ft mark, but they would not be in the 1/3 range, but rather right AT the 1/3 mark. Is this still acceptable? If not, could I have part of the tie in the lower 1/3 and part above it? If I were to have the entire rafter tie in the lower 1/3, I'd have a door opening of only 79" rough opening.