Hence the reason I've recommended hardware cloth, available at virtually any hardware store, including the big box ones, that you can find. It's got the "structural stiffness" needed, yet can very easily be trimmed to shape using metal snips (probably even scissors, though you'd make those scissors useless for other purposes).
I'll have to take a photo of what's in SRH33576 if I can get a chance over the next several days. I basically used the actual grille as my template, but cut in around the entire perimeter just enough so the grille didn't collide with it. I also remember having to cut out a spot for the washer jet at the center and (perhaps) something else.