Thanks for the detail. This is super helpful.
The only thing I can think of is changing the 302 to a 301. I looked at doing a curl against a twitter URL and saw this:
- Connected to t.co (199.59.150.44) port 80 (#0)
GET /RAFOoJrOD2 HTTP/1.1
Host: t.co
Accept: /
User-Agent:TwitterBot
< HTTP/1.1 301 Moved Permanently
< cache-control: private,max-age=300
< date: Tue, 01 Oct 2013 16:35:06 GMT
< expires: Thu, 01-Jan-1970 00:00:00 GMT
< location: http://cardstest2.blogspot.com/2013/09/barnotes2.html
< server: tfe
< set-cookie: muc=1;Domain=t.co;Expires=Sun, 13-Sep-2015 16:35:06 GMT
< Content-Length: 0