I vote use whatever name the winery uses so if I see a Petite Syrah I know to avoid. If you can order wine online, you can Google.
@KNmeh7 Yeah. Kinda the same. I also see it as a style choice. If a winery chooses Cinsaut vs. Cinsault, that is a choice. And as a consumer i can read in to that choice. Seeing a Mataro labeled as such makes me think – and i enjoy that.
My California Shiraz is your Petite Syrah.