Black is the best color for ANY days. White dissappears in all but the blues skys and is hard to see. Light colors in general are hard to focus on when your trying to watch your plane, your opponents plane and trying to avoid mid-airs.

that tape is also thinner in width would would be harder to see than the crape paper cut in half... and expensive!

but I guess for a rainy day, it would be an option, if you don't have anything else...