It's(the spring) not there to add compression but for "shock resistance" to the load of being coupled.
Here's my ?.
What does that bar do? What does it do under load of acceleration? What does it do when the suspension is compressed?
The way I understand it is the more you crank the nut the more ski pressure you create..I actually removed mine for a ride.
it bottomed more, but felt good.and was definitely fun. I have reinstalled it..
I believe it stretches when the suspension is compressed.