I shot the Phlex on Rails video course outside last summer with a glossy screen and barely notice reflections or glare, mainly because I setup shop under the shade of large oak trees. The bigger issue with direct sunlight is the glare off the chassis and heat, even when it’s 75F/24C outside.

I wrote about it at https://beautifulruby.com/articles/portable-workstation-iter... if you want to see the setup.