It was surprisingly difficult to find what I thought might be suitable colours for A&A's main sign. I finally settled on some Tamyia red and orange in spray cans.
I sprayed the backs of the sign pieces with appropriate colours, but the application turned out a bit mottled - even after some test pieces suggested the paint would go on clean and smooth. Clearly, I didn't properly clean the surfaces.
Also, there was some overspray on the front surface - which I wanted to remain paint-free and glossy - where I didn't fully seal the masking tape.
Basically, I need to cut 2 new pieces and try again.