toilet base plate

my basement concrete floor is not even and not finish yet. but i want install a toilet as soon as possible. I am thinking put a toilet base plate to make it easy for the toilet installation and later floor finishment. do you think this is a good idea? and are all different toilets have the same shape and size or similar base? thanks

There is no "generic" size OR shape. Every model, not just make, is different. Install the toilet on the concrete and then remove it when you do the floor tile.

Ideally, the toilet flange is installed on top of the finished floor. So, you might consider setting the toilet on say a chunk of ply that is the approximate thickness of your new floor. It will work if the floor isn't too thick if your flange is flat on top of the concrete, but the preferred place is on top of the finished floor. You may need an extra thick wax ring once you install it after the new floor is in place, or stack two standard ones.