I have had limited success with Lucas. My favorite is Trans-X. I think they fight the issue from opposite directions. Lucas will thicken your transmission's fluid while Trans-X will thin it out. What you want depends on whether you are fighting worn/glazed clutches, sticky valves, or leaking piston seals.
In either case, these things are referred to as "MIRACLE IN A CAN" fixes. I would not expect either one to buy you a lot of time. As for a flush & fill, it might help, but I doubt it. Your tranny is probably on its way out.
I posted http://wichita.craigslist.org/pts/359579252.html for another reader a little while ago. He might be worth a shot for you too, but only if you're nearby. I've gotten some good parts there before.