Have you considered a site like https://points.com? You can trade 8,500 AS points for 783 AA points; while you wouldn't be getting maximum utility from your points (as you would by applying them to an AS account) you could inherit an addition 283 points (you may find this negligable relative to the size of your accounts). Otherwise, I'd go for the 8,500 and build the account up with hotel and product offers. Good luck next season!