The aperture grill is definitely a compromise right now. I found that for 1920x1080 displays I liked the grill fixed to output pixels instead of getting warped, because there just is not enough pixels per grill element to do a good proper simulation if a real pattern. Reason why it is rotated 90 degrees, less chromatic issues on the scanlines.
Grill should definitely be a loadable option with warp/no-warp check-box, but could not do loadable image in shadertoy. Perhaps if I get time I will try a few more options: like trinitron, vga dot pattern, etc...