Ok, two stories for the ballers out there. A 3rd round at Bel Aqua 20+ years ago, they made up loops that compensated for everyone's reach. Shorter guys got a longer loop, taller guys still got a loop, but shorter. At the end of the round, most skied a couple balls better, but the interesting thing was that the placement was still about the same as the tournament results, so reach didn't seem to be a clear factor in how everyone skied.
Next, I was skiing off the hook in early 2010, running 38's like candy, ran a few 39's. I picked up new rope the previous fall. After skiing with this rope for 4 months, the week before nationals someone kindly said, "you're running those 38's too easy...better check your rope" Sure enough, they had made a switch rope too long, the switch section was out, but the main section was too long. Talk about a mind melt before nats! I now have marks on my deck.