Wow! Sincerely yours you really did a great job and I love the way you were updating people from step to step. I'm also a fan of shed building and I have some amazing sheds too. You may want to take a look https://www.urban-sheds.com/
I would have suggest you use a cardboard or garage mat because it's almost impossible to get a concrete that will be dry in a very short time. But looking at Armorpoxy comment, I feel you should try and give his brand a chance since it's a special product they don't even showcase on their site...