You also should consider that there will be a time that you will have to use a lift, whether it is to transfer onto the toilet or onto a commode/showerchair. We have a ceiling lift, but others have used a portable hoyer lift, which means there has to be room to pivot it and enough room on either side of the toilet. A ceiling lift does require less room, but is not always practical. Tim has a very large chair as he is a tall man, so we have room to park his pwc, and place his commode/shower chair beside him, and transfer him over. We did have the benefit of designing and building the house around his needs though.
I one PALS home that we met in Seattle he had a 5' X 5' bathroom off of his bedroom (which use to be the dining room) and in it was the toilet, and stainless steel corner sink, and telephone shower. His aide parked his chair just outside of it, did a turn transfer (he was light enough, but they did have a ceiling lift if needed.) and did his morning care while he was on the toilet, including the shower. There was a drain in the floor, and the entire thing was tiled. When done they just closed the pocket door, and you wouldn't have known it was there.
Paulette