Pit Monkey,
I apecaite the trust my freind but many of the kindly readers here can offer plenty of help!
Anyway the preload is adjusted by first unlocking the lock ring and then in your case I imagine losening the spring. You can turn the spring and tensioing ring by hnad usualy.. But don't beat on it with a hammer and punch, if you kust take the shock off and soak it in penetrant before risking thread damage or haking up a ring..
Your springs are more than a touch heavy for you but see what you come up with sag numbers.
Does that clear it up some?
Jer