No Lift 360 Swap Tips/Suggestions

My landlord is a piece of work, but he is letting me do this! That section of garage hand an inch of mud, and junk everywhere for the last 2 years, now it’s functional, and I solved his water problem. He has a lift in the main part. Gravel? I’d build a wood floor. Carpentry is one of my trades, so theres that lol. I definitely thought about those supports being on the inside versus outside, and prefer outside with much thicker metal.