I made mine 45X45 with 2 ea 14X14 doors. Wish I had made it larger. Sloped the floor 1/4" towards the doors so I can wash RV inside. RV is plugged into 50A. Made floor 13" thick.
Made work bench 45' long and laid out lots of tools for easy access.
My wife and I installed the Blue Ox baseplate on our 2015 JKU in about 2 hours. Easy but takes 2 people. Yes, I do have a car lift in the workshop.
We transferred our BB from a Durango to the Wrangler.