I just received a 24" Red Dot Artar I won on that auction site and it's mounted to about a 3.5" barrel with ~ a 4"x4" plate, like an extended lens board. I figure there would be no problem with 4x5 film, but I want to use it with 8x10. Without buying a lensboard for this setup is there a way I can figure out whether or not this will vignette with 8x10 at infinity? For an extra 3" of bellows draw I definitely want to use it this way if it's practicable. Thanks.

This is a link to the listing with photos.