Allow me to assist in this regard...
For
mhenn1965's' benefit (please clarify/update me if needed), I would think that the targets used would be either of these. The black ones were used at the time I was involved in SR locally, and were great for those using iron sights (6 oclock hold) as they really contrasted well with the backboards. Now that most everyone is using optics, perhaps the targets on the right (figure 12's) are being used now(?).
Regardless, the dimensions are the same--18" wide and 22" tall with 6" and 12" rings. I suppose you can "scribe" a 3" V-bull with a math set compass to practice on, and use the chin of the figure 12 as an aimpoint.....