I used "cheap" 'static cling' sun shade from the local auto parts store. 17 or 18 years ago I paid about $12 USD and cut it to make three pieces. I used two and do not remember what I did with the 3rd. Just like on aluminum, I have rounded corners.
The Kroger shade was about $170 back then. Being a 'cheap' pilot, I did not want to spend that much so figured if the $12 worked for a year or two, I would then opt for the Kroger Shade. Well more than 17-years later, I still like what I have. IF out "Dog Fighting", one can see right trough the 'static cling' tint and acquire the target.