Is that still the balloon shaped
salon roof? That has to be a challenge. You may be able to form a
mold for
fiberglass trim pieces by sticking on 3/4" foam
freezer tape to fit, spraying with light
adhesive, covering with stretchy felt, and stiffening with sprayed gel coat. When the gel coat has cured, you peel sections at a time, remove the foam and put a layer or two of glass matt on the inside of the felt. It will be an awful mess to clean up if you don't carpet the entire space with drip cloth.
Work on one frame at a time, and use contoured foam for a nice look. Dents or wrinkles in the foam and the felt can be filled with micro balloons.
This is how custom speaker housings for cars are built.