I found some time to shoot some resolutions (up to 4k) into my Ultra. It´s consumer 4k at 3840x2160 run in an 2,4:1 (22:9) aspect ratio resulting in an 3840 * 1600 resolution.
I use a Marquee 9500 Ultra with high resolution tubes (PT22) and HD10R5M curve screen lenses. The lenses are made for curve screens and based on the plain HD10 lenses.
So there should be more resolution possible with HFQs. The test pattern shows one pixel as one line, so the better you see each single line the better the resolution is resolved.
As 4k with one single projector was... well look for youself in the video, I also added blend resolutions. They got mastered by the Ultra!