I like to think of the secondary as a torque sensing device. When there is extra torque from the engine, enough to turn the track in the conditions, plus some, then the secondary will allow the sheeves to move apart, reducing drive ratio. It seems like the engine torque causes the sheeve to "climb" up the helix ramp against the spring. When there is not enough torque, the track (via the driveshaft) will pull the sheeve back down the helix, forcing the belt back out of the secondary to a higher drive ratio.
That may not be technically correct, but it helps me visualize the forces and actions.
Yes, M7, the orange spring should work better for you than the white at any preload setting. As you add preload to the white, it does start to backshift better, but the extra spring force limits total upshift (by adding preload, you increase the spring pressure at the start of the shift, but also at the end, by the same amount).
Frosty, it may be worth playing with if you change altitude a lot, but I found with a good secondary spring, it is not that necessary. I do need to remember that trick, though, next time I need a little more at the high end of my normal altitude range.
John