I know exactly what you mean, and I know exactly how to fix it! You need to build a small hood and angle it at about 30 degrees to the screen. You lose very little by looking at the screen at an angle, and no more reflection of your face, or of the sky. I attach photos of my hood. I have also built a small platform for the mobile and angled this forwards by 25 degrees. The end result is that the hood angles back about 5 dergees with respect to the controller, and I find this perfect for viewing for extended periods.
I attach a photo to give you the idea. The mobile support is made of wood and the hood of fairly stiff plastic. The hood is held on by elastcated velcro and folds flat for transport. It works great, even in bright sunshine.
Thanks a lot for letting me know about your device; it sure does look as if it can be the solution for my "blindness". Just received my matte finish screen protection, so now it is just a question of buying the material you used to make myself one. Will keep in touch and inform you of how I managed....