I have the square labels for 360 panels so probably not much use for you. In regard to a somewhat related issue ... I don't think I understand the back light operation completely. On my new DC panel, all of the back lights work nicely with a green glow, but when I stuck on all the labels, the back light is covered up and doesn't shine thru the label. I was expecting the light to shine thru the lettering to see nice green letters in the dark. Instead, the white lettering on the labels appears to be opaque, so I see nothing in the dark as the back light is completely covered. Did I not install the labels correctly? They appeared to be simple peel and stick (and they really stick well).
My new ELCI panel had 3 labels pre-installed (ELCI, AC MAIN, REVERSE POLARITY) and the green light shows thru the lettering very nicely. The branch panel has the back lights and I haven't stuck the labels on yet, hoping I'll find a way to see the light.