Back in the day, many VW dealers started to apply light grey dealership livery to the inside of the glass, iirc the font used was/is called "VW" and I'm also sure that the "GolfGTI" logo is that same font... JV where are you!

I'd put them in the bottom corner of the rear side window, like they used to... with a 40mm gap from the edge of the glass, close to the seatbelt

Thom