Hey, I'm curious if preload affects a leaf spring differently than a coil spring...

I'm going to install my Tokico trek master kit with the composit leafs and I'm trying to figure out if I should set the snubbers on with the full preload or put some room in between them and the springs. Obviously I can see how it would impact the springs if the load leaf is in constant contact, I'm just curious if the preload also increases the spring rate as opposed to a coil spring that stays constant, as long as the rate is linear. Thats counting if the load leaf is added in to the overall rate.

As a subquestion, does anybody have any suggestions as far as how it works on their rig, I searched a little but didn't come up with any specifics. Thanks for the help!