Specifics: 95 yr old garage, double brick walls, 27' deep x 42' wide. Load bearing wall slightly more than half way across the 42" and an approx 12"x12" split (2 - 6"x12") support running the width of each half. Rafters are 2x6x16 on one half of garage and 2x8x16 in the other portion (other side...