Good link and interesting read...

As foor Woods question, you can work out what the change in Rake will be, but you will need some basic maths and a measuring tape...

Not sure if this is the easiest way... but using the diagram attached..

where x is current rake angle
A is height frame mount where it hits the top of the shock from the line B taken from front axle (you can measure from A to ground then subtract height of front axle to ground)
B is distance of front axle to verticle line of shockmount.
get ya calculator now...if my memory is working (been a while )
Tan Z = A/B, this will give you Angle Z
You already know angle X
and X+Y+Z = 90 degrees...
Now alter A to be A+7
Work out Z again as above
As Y is constant as is the verticle line at the front axle,
The change in angle Z will give you the decrease in angle X, which is the Rake. : )

Most importantly... does it matter.... ?
If I told you that the rake changed from 23deg to 21.97364840 would it matter ?? (those are not the correct numbers by the way)

Regs,
VTRBeefa