I am a suction cup sun shade user. $10 each at big box stores, and you can position them exactly where you want them. I occasionally get whacked in the head when a suction cup breaks loose. I kind of like that wake up call, so I put it back in the same place, over and over, and get whacked again.
I do this because I can't stand to sacrifice visibility for shade, like one must with the rail system of certain shades. You find a way to mount a quality shade over the top half of a tip up, that is removable when not needed, but still stays in place, and does not rub against my headset, I'd give you $200.