What do you guys think about this angle?

From the link you posted:
Preload is a measurement of how much a spring is compressed at full extension of the shock.
Thread the upper spring adjuster down until it just touches the spring, you are now at 0″ of preload.
Every inch you thread it down from there is 1″ of preload

it’s literally the exposed threads. Again, it’s not consistent and at times you need more or less preload to achieve the same lift height but preload is based on compression of the spring AKA threads exposed.

 

I’m just going to leave this gem. Night everyone.

 

Spring rate is good and all, but then there's wheel rate or effective spring rate.
Check out figure 2 in the link and the equation right above it and imagine changing the 'angles of the dangles' and wheel offset.
http://www.thecartech.com/subjects/design/suspension_formulas.htm

 

Preload is not really to set ride height, it’s to set static sag / how much down force you want. Ride height is just one of the unintended consequences of adding preload. I agree most People on this forum seem to incorrectness use it just because they want to add ride height, like the first picture.