Perhaps a picture will help, this is a typical motocycle shock design.



Regardless of the theory you guys choose to espouse the reality is that cranking t-bars always has and always will sitffen the suspension. If you take some leaf springs and bring the ends closer together thus resulting in a steeper arc and some lift do you not think they would be stiffer than they were? Have you ever used a bow and arrow? Do you think it is as easy to pull the last 6" as the first? No way unless it is a compound. I don't care what any of you say about the "linear" springs rates, all springs will require increasing force as they compress, it is a fact of life. Yes the steel in springs can deform, that's why they are springs, but they also resist deformation, or they would collapse with a load on them.