14 is as short as you should go if you want a tall 4 post lift. I have 14 in one building with a clear span so it’s 16 in center. I was wondering about the foam spray. They want 5500 for 1 inch foam ceiling and sides. How thick did you go with the spray foam? And does it help? I have another garage 30x45x18 with 6 inch fiberglass and it helps both in summer and winter. Thanks