I'm just getting back into offhand shooting after a loooooong layoff. I'm shooting rifles with essentially no error at 50 yards.

What's a realistic target size? Three inches? Two inches?

Been a long time since you posted but I just read this.

The high power aiming bull is about 12" at 200 yards, corresponding to 3" at 50 yards. That bull scores a 9 or 10. Unless you are a very good shot, I'd start with 6" targets at 50 yards and then get smaller as you get better.