We found on the T with the old rig when going wild downwind that heeling the boat created lift from the bow and reduced the tendency to dive. It is a fine line between safe and fast on the T and I would imagine even harder to do on a narrow boat like a mozzie.
With the kite up I would highly recomend you guys work out a way to get further back. On the new rig T we thought we were as far back as possible then worked out that we could go Way faster in a blow if the crew traped off the rudder with his back foot and front foot on the transom, this is tricky but makes a massive difference.
As for adjusting the rake on the fly.... Well if you want that kind of mess on your boat why not sail a 505? But seriously why not increase the rake on you boat until the upwind performance drops off (you will be suprised how far back you can rake it and still be fast) you will have to bring your rudders under the boat a bit more.