I just noticed the class rules only allow certain color sail numbers. Seems odd that the rules would not simply state a "visibly contrasting color" to the sail. I happy to go with one of the allowed colors as to be frank, you can hardly see them blue or green on a 3di sail. I was about to order a black 3di sail with white numbers, but it appears the class doesnâ€®t allow white sail numbers? Is this correct?