I think a 24" diameter circle will give the right amount of room to space disks.
I just used numbers 1 to 10 for the disks. The center is 50 and the small area around the center is 25.
Just like darts inner ring is a triple middle ring is a double and outer ring is marked value.
Many games could be played on this just like darts.
The way we battle is everyone throws at the same time. If you land in a cup that's your score. If you land on the board but not in a cup it's 1 point. Long spin gets a 5 point kicker each round. I like this way to keep rules simple with many people.