To handle the Wolf extra fat, we initially decided to try Progressive Suspension progressive fork springs, Ref. 11-1510 and Procycle linear 7.5 kg/mm rear spring.
We liked the result but felt the bike still squatted excessively when loaded. We transferred that setup to the Zebramobile and ordered from Procycle a 8.3 kg/mm rear spring and 0.70 kg/mm linear fork springs for the Wolfmobile.

Update: June 27, 2014
After over 5000kms on and off-road we found that:
– the progressive fork springs with the stock preload work very well, providing a plush but not mushy ride
– the rear 7.5kg/mm linear spring sags excessively with our luggage, adding preload alleviated the problem and we are overall happy with the Zebra mobile setup.
– the 0.7kg/mm linear fork springs are too stiff. They overwhelm the hydraulic even with 15W oil and the sag cannot be set properly.
– the 8.3kg/mm linear rear spring requires minimum preload and works well with a loaded bike. The hydraulic are falling behind but less noticeably than the forks with 0.7 springs.