Replace the semi fiber clutch disc with a full fiber disc, pull the judder springs and replace three of the six clutch hub springs with heavier ones and you will be good to go. There are not very many options when it comes to clutch parts for the xx.
You can actually buy everything from your local Honda dealer also, just make sure you get the correct fiber. (Not the part number with a quantity of one, it is the part number with a quantity of 6 I believe.) The fibers used in the TRX450R are the same part number as the 700XX ones, so I already had a few extra fibers laying around.
As for springs, I also used what 450R guys are using, CR500 springs. The part numbers of the springs are also the same between the 450R and 700XX and I know alot of people who use CR500 springs as heavy duty springs in their 450R, so figured I would give it a shot in the 700XX also. (I just ordered 2001 CR500 springs, but I think they have been the same for the last decade the CR500 was produced.) I ordered 6 CR500 springs, but not exactly sure how many I will use yet, will experiment some to see how stiff the clutch lever gets.
Haven't had a chance to try the clutch yet, motor has been apart getting some work done, hopefully I will have it back together in a couple more weeks.