Ah, EdgePeek helps, but I can’t seem to use it in the menus so I guess the key is to launch the game and then set the resolution.
The Vive Pro is 2880 x 1600 resolution for both eyes but that is what is causing the flicker and generates the message to use a 4×3 resolution. I already have the resolution of 2560×1600 in my Nvidia Control Panel, but this resolution doesn’t show up when I go into the HL2 Video options. Is 2048 x 1536 my best option? Is there any way to get a crosshair back?