I am looking for information that will help me with product design for
a new paint roller for painting ceilings.  Specifically, I am seeking
to understand the ergonomic factors for a good product design that
will reduce risk of hand, wrist, neck and shoulder fatigue associated
with painting ceilings over a long period of time

Have you tried researching Michaelangelo? he was painting the ceiling
for five years. I think he found it best laying on his back on some
scaffold.