This might be dumb ass question, but I wanna be sure so I don't end up misleading my fried homies at the park: changing the height of the top bushing in a truck doesn't affect the truck's overall geometry (such as the wb effect), right? Only the bottom bushing affects that, no?
Ok that was two questions. But still. Thanks.
It is a funny one, with some people saying it does and others saying it doesn't, but keeping bottom bushing and washer as is will keep the geometry and overall wheelbase. Changing the bottom bushing to a different shape - conical or cylinder, making it lower / taller or removing the washer will all have different effects on how the truck performs.
Changing height of the top one will change how much the truck will turn, usually a taller top bushing than what is on there means the turn might be less and resistance is going to be stiffer, but having a lower top bushing means the truck will be looser (unless tightened right down) so it will turn a lot more and have less resistance.
If tightened down, the top washer might hit the hanger a lot more too, so although the overall turn might be easier, it will get to a certain point and stop, or not turn much past that point, as per boards I have with minimal top bushings.
There are probably a few other options I could provide info on, but I will leave it at that for now.