Our original post is two years old! andye bumped it to the top with his own question.
We did have the heavier spring put on front, and they helped. But it didn't stop the retraction problem entirely. We had trouble when we visited WRV for factory service in August of 2006, and they sprayed the jacks with Dupont Teflon Silicon lubricant which is safe for all surfaces. The jacks then retracted super fast!
So now, every couple of months or so, when one of our jacks is very slow to retract, we spray it with that stuff. That's basically how we manage our jack retraction problem.
36ft 2006 Alpine Coach FDDS