Back in the day, we would shoot our 7 1/2 and 15 yd stages on centers only (B 27C) then used the B 27 at 25 and the reduced target (AKA "the D**n Dwarf") at 25 to simulate the 50. Of course this was a casual, unofficial league. The reason for using centers at the short ranges was that at those ranges, if you couldn't stay in the 8 and 9 ring or better, you weren't shooting anyway!

BTW, we just stapled the targets to cardboard backers that were clipped to the carriers.

Froggie