Hi, I have a really rough concrete floor I want to smooth up so I can lay vinyl tile, the kind you paste. I tried mixing Fix All but it didn't just level itself and it's as hard to sand as concrete is. Can anyone tell me how much water to how much powder would work? This is a really big floor and I'm not good at troweling so if I could just pour it and let it dry would be great. I will be grateful for any advice.