Going forward in case anyone else reads this thread asking for advice on how to rescind: the best way to rescind is very simple--write the letter, have all parties to the contract sign it, keep a copy for yourself, mail it at the post office by certified mail, keep the receipt from the post office that will show that you rescinded within the time period. If your contract specifies that you have it notarized and that you must sent it by priority overnight requiring a signature, then of course that's what you should do. Most contracts don't specify that though.
DaveGTR11, if it makes you feel better to do what you did, that's fine. But what does your sales contract say about how to rescind? Whatever it says is what you should do. Of course some timeshare sales dept. make it very difficult to even find the instructions for rescission. But, the generally legally accepted proof of mailing is just a certified mail receipt from the USPS.