More ideas . . .
In NRA smallbore tournaments, where we have a large black aiming bull, it is sometimes hard to see a shot in the black. NRA's answer to that is to have circles cut in the target frame just a little larger than the size of the black. Light shines through the bullet holes for easier visibility.
Years ago we built Camp Perry type frames at our club. They have the holes cut out behind the black bulls for 50 yard and 100 yard NRA targets.They also hold plan white backer cards for checking for cross fires. Placing the white backer 6 inches behind the record target would show a cross fire displaced by one bullet hole, from the shooter next to you. For 100 yards, placing the backer 12 inches behind the target gives a one bullet hole displacement. (Two bullet holes from a shooter two positions away from you)
On another board I mentioned the difficulty of seeing bullet holes on the NRA 200 yard Smallbore target with it's black 12 inch aiming bull. Another shooter had a solution to that problem. He said if you place a yellow or red backer behind the target, the bullet holes appear as bright colored dots. The frame holding the record target must have a hole the size of the aiming black, and the colored backer should be placed at least 6 inches behind the record target.
Our 25 bull benchrest targets could give cleaner holes, and the backers might last longer, if we cut out holes behind each of the 25 bulls. That's a lot of work for little gain. Holes are easy to see at 50 yards on our targets. But: The holes in the target could be cleaner: When a bullet goes through the backer in an area there it hits part of a hole and part of the backer paper, it may show a tipped or ragged hole.
As for the qualtliy of target paper. At least two printing companies still use tagboard for tournament quality targets: American Target Company and National Target Company. They both hold license from NRA. The American Target company also prints the USBR targets. Some other printers do not use tagboard.
Joe