Bathroom remodel - floors before walls or vice-versa

I'm remodeling a bathroom and doing 4' of drywall at the top with 5' of pine T&G plank chair rail below it. The floor is going to be 3/4" ceramic penny round tiles.

The ceiling and the 4' of drywall at the top are already finished.

I was planning on doing the tile next, and then doing the chair rail.

However, I'm now questioning this decision because I'm not sure exactly where the chair rail is going to come out with respect to the tile. For instance, I haven't picked out a baseboard yet, and haven't decided if I want to do shoe molding. Also, all the original trim in the bathroom (door casing, window casing) is all ripped out, waiting to be stripped.

I just have a fear of putting the floor down and then finding out there is a sliver of tile along one wall.

Thoughts?

Also, does anyone know of a baseboard that is notched to accept 3/4" T&G planks? Every one I have seen is notched 1/4" for the beadboard panels.

Thanks all.