This link has a good discussion on the impact of preload on droop.
https://accutuneoffroad.com/articles/spring-preload-matters/
In short, in addition to the ride height change, adding preload will cause the spring to extend with relatively more force at the more extreme droop extensions. On my gen 2, I tried 3/4" preload (1.5" ride height) on my Fox Factory set up, and I hated it. In large part, this was because the truck had less down travel, and because of how hard it hit the full end of that down travel. This article helps explain that. I think it is also important for everyone reading this to understand that the collar or SDI spacers create 1.5" of lift (or whatever the number is), not by being 1.5" high, but through a 2:1 ratio (so 1.5" lift is actually a 0.75" spacer - or it should be). I ended up lowering my truck to have 3/8 preload on the Factory coilovers, to achieve 3/4" of added ride height, and was quite happy with that. Another thing to consider is that by moving the truck's static height, you change the point at which the various bypass valves are engaged. Too much and you're out of the engineered range, and the bypass valves aren't doing the right things at the right times. Finally, for live valve trucks, it is important to reset the computer to a new zero static ride height. Otherwise the shocks will be instructed by the computer to do things you don't want, as the computer thinks something else is happening based on the read of shock position.
