Masking tape

I use strips of the tan masking tape for seat belts and shoulder harnesses.  The right color for certain era belts, cheap, and self adhesive.  I have either used them with PE fittings, or for smaller scales just paint the fittings on with steel or flat aluminum paint.

I've used masking tape for several items like this including canopy frames.

tape a piece to a hard surface, I use glass, paint it, then cut your desired width strips with a sharp blade. After installing your painted tape strip paint  it with a clear coat like future or clear paint to seal it in.  Cheers.