Woo-hoo. Now that I can post links, I can show y'all what I meant before.
http://jas.familyfun.go.com/healthto...=OptWeightForm
If you look in the text on the left, it has a link in Step 2 that tells you how to find your frame size. If you use a measuring tape and the chart on the page in the link, you can find it easily. Then, you can plug in your info and have a more accurate weight. It does clearly explain that it will not be accurate for those with an "athletic" build (who have more muscle mass than typical for their size).
HTH