The proportions are wrong. For a 4 x 3 (conventional screen with a height of 48 inches, the board should be 64 inches wide. This yields a diagonal measurement of 80 inches which is decent for a line doubled Marquee 8000.
If you want to go with a 16 x 9 ratio, then for a screen height of 48 inches, the width should be 85 1/3 inches and the corresponding diagonal measurement is just shy of 98".
Although this is within the normal range of a Marquee 8000, I think you'd be a little disappointed with a picture this large with only a line doubler. IMO, scan lines would be obvious.
Either way, you'll probably want to mask the sides of the 4 x 8 board with something like black velvet to reduce the size to normal video dimensions.
Jeff HIpps
If you want to go with a 16 x 9 ratio, then for a screen height of 48 inches, the width should be 85 1/3 inches and the corresponding diagonal measurement is just shy of 98".
Although this is within the normal range of a Marquee 8000, I think you'd be a little disappointed with a picture this large with only a line doubler. IMO, scan lines would be obvious.
Either way, you'll probably want to mask the sides of the 4 x 8 board with something like black velvet to reduce the size to normal video dimensions.
Jeff HIpps