I recently had a vinyl floor installed in a bathroom, and removed the toilet beforehand. Now it's time to replace the toilet, but I am not sure what to do about the flange. It's intact, but slightly uneven. The back portion is just above the vinyl flooring, but the front dips down very slightly (less than 1/2") and is just underneath the vinyl floor. I am not sure if I need to install some sort of extender, or if the wax ring with be fine to deal with the unevenness.
I also removed the existing screws that affix the flange to the floor because they were rusty. Now should I install slightly larger diameter screws, and what material should they be made of?