@tails The top ring can be turned to increase the preload. Make sure to adjust them equally. A Scotsman could do it by hand if he had porridge for breakfast or you could use a non marring rubber strap wrench.
You just need them set up correctly and as Paul said eat some porridge then you can turn them with two fingers or you can get a cheeeep strap wrench that makes it a lot easier and as said do both sides equally.
If I remember correctly the top of the shock just below where the bolt goes thru has about four or five rings that is how you know how much to adjust each side or you can always check out the progressive web site
u are using a shock that is shorter than normal and if that spring is weak u might want to keep an eye on the wiring under the fender to make sure u don't rub the wiring and cause u troubles.