the stone floor is very thick and can 'embed' into the ground. It will hide fairly large gaps.
If you do not want to use flooring, you need a lot of patience to level it. I use wood floor tiles to validate that it is nearly level, they also embed and the dirt is above or below them makes it easy to see how close to flat you are and where you need to work.
The cultivator and the paved road are alternatives to hoe flatten and sometimes one or another works better on a tough spot. The paved road costs rocks and changes the look, so you may or may not care for it. Cultivator makes it black, of course.