We added a stair rail in our 3611JS Cyclone and it is so sturdy you could do pull ups on this!
We purchased from Amazon because this was the only reasonably priced 12" grab bar of quality that we could locate. I have attached a couple of photos. Now I no longer have to put my hands on the wall to brace myself going up and down the steps.
Unfortunately I am not able to assist you with a grab bar for the tub, it sure would be nice, I know I am very careful stepping in and out of the tub.
Sorry for the duplicate pics I could not figure out how to delete the duplicate.
Susan & Gary