M.R.
What's the bucket for?
I just fill up the tub, let them soak and use a bunched up or folded large towel under my knees and one draped over the side of the tub to lean on.
I do recall my chest bone aching some while leaning over the side of the tub while washing and rinsing hair. But then I had my husband install a hand held shower head, so I could rinse with that so I did not have to lean over for so long
HTH!