Great! His description on preload reveals an often overlooked issue for good rear spring tuning.

 

Thanks for all the replies! I just found the easiest way to put more preload on the shock spring. Just loosen the locknut and turn the spring by hand (fairly easy) the first nut will turn with the spring. No need to use a punch and hammer to adjust, but you will need a punch and hammer to tighten the locknut back up.