Lots of variables would come into play for me. If one is a big 8 and the other a 10 or more, I'd shoot the 8. If I had pictures of both from the year before, I'd shoot the one that improved the least. If they score roughly the same (+/- 5to10 inches) I'd shoot the older one. If nothing is known, it would come down to fencing....High fence, shoot the Old one. Low fence, shoot the Big one.