Refinishing fiberglass windows and frames

[Sparktrician]

I've been approached by a good customer that wants me to adjust the inside color of the fiberglass windows and frames from the current beige to white.  I've never painted fiberglass windows before, and wonder about the best approach to doing so.  Spraying is not a realistic option in this case, leaving only brushing on a finish.  I'm looking for input from those more experienced in finishing on the best way (methodology and products) to address this. 

 

[duburban]

I'd call manufacturer asap.