We have an acrylic bathtub that my wife uses every day. At our
previous place we had a 'soaking' tub that my wife loved.
The problem is that the new tub is too long and the back rest is too
steep for her comfort. She is always sliding down as she bathes.
I can think of a few ideas to modify the tub.
1> Find an acrylic manufacturer who could cut some panels to be
adhesively fastened to:
a. shorten the tub interior
b. modify the slope at the head end.
2> Use plywood to do the above and either tile the plywood or ask a
professional epoxy refinsisher to coat the bare plywood.