Hi twinn
I built a pole barn/garage at my old house last year for my 29. All local building codes dictate what u can and cant do but for here in my area in NY pole barn/floating concrete slab was the best and most affordable way to go for me. It was 38'x50' 10' high ceilings two doors 10'x9'. The great part about the pole building is you don't have the added cost of a stem wall/footer. I built a second story with two large dormers and left a large area 10'x10' of the second floor open with the future idea of having clearance to pull motors. I also sided and shingled the building to match my house, it looked great and was very affordable to build(I did all the labor myself). My friend liked it so much after I was done he bought my house and the new barn! I only got to store my boat in it last winter! The next one I build I plan to do a little diff. at 50' deep I was just 2' shy of being able to leave my F150 hooked up to the boat in the one bay. And the 10'x9' doors I would recommend changing to 12'x9'. The full second story was also a little bit of an overkill. I'm a builder so if you have any questions feel free to write me and good luck.
Scott