Bill,
I'm guessing thats the GT1000 Ducatti? Regarless, progressive springs ( not to be confussed with Dual Rate Springs) are very difficult to tame (Calculate correct sag and squat) to any machine in a single mono shock application..... Dual Shocks with a Progressive Spring are problematic at best.... Unless you know the Spring Rates and have tried someone elses machine with them on and the Pre-load was just for you......... Yeah, I know, in a perfect world!
We shy away from progressive unless (as in your case) we have exhausted our search for manufacturers that offer the other tyes of springs. Progressive applications would typically be for a rider or riders who are doing extreme off road riding or abusing the Max Load Rating of the street machine they own. A Progressive Spring is the hardest to calculate the Static, Ride Sag and Bikes Squat.
For Example, If I have a rider with a KTM 520 EXC who is coming in at 110 kilos and is almost 195cm tall..... It's going to have to be a Progressive for his size and Extreme Riding Off Road. The other side of the "Progressive spectrum" is our fellow Thailand natives who need to have a PCX150 to commute solo everyday and can also "Double Duty" as a "Family Wagon" and grab up the wife and kiddies after school and work...... This is truly where a Progressive Spring is needed.
Ill assume you ride the street, on that Liter Bike we would have suggested a Dual Rate w/remote resivoir in Rear and dual rate front spring set to balance out the front squat...... Marzzuchi would have been my first suggestion, but as they are now out of business, we would recommend Ohlins or Wilbers.
Listed in the Below Pic are typical of the 3 springs available to power sports.
View attachment 4127
Cheers