When we did our bathroom remodel, I had 7 grab bars put in it as the shower is approximately 6'x6'. I also had a wand shower head put in. Unfortunately, by the time the remodel was complete, my DH could no longer stand long enough to shower.
Shower chair #1 was a stationary model. He could still stand for transfers.
Shower chair #2 came as a donation from the ALS loan closet. It was a rolling/tilting shower commode chair that was just a little too small for DH, but we made it work. By then, we were using a transfer board.
Shower chair #3, the current one is also a rolling/tilting shower commode chair. The brand is Aqua Tec. My aunt had a friend who's husband was a disabled vet, so the VA provided it, but he preferred bed baths, so we got the chair brand new. It is by far the best, and thank God. We now are 100% hoyer lift for transfers. DH uses it not only in the shower, but as a commode too. His trunk and neck support have weakened to the point where he cannot sit up straight alone. I find it easier to position him in the chair because it can recline so that he sits back far enough. For showers, we get him in the chair then roll it into the shower once the water is warm. The shower is big enough for me or his aide to be in there with him in the chair. For toileting, we position the chair with the brakes on and get him in with the hoyer. Then I can tilt it slightly forward so he can "go".
I would strongly suggest one that tilts/reclines as it may be needed as things progress.