[dsraven]

lower control arms need to be level at ride height. if they are not then you would find yourself bottoming out over bumps where you normally wouldn't. another, stronger, set of springs would be indicated to level the lower control arm when sitting on a level surface. a new set of springs will be stronger right out of the chute so the truck will ride high for a bit until they get their "set". with that said, if those current springs are new then the truck will sag a bit more and make it worse. if you do go with the spacers then you should also check the bump stops to ensure they are set up so they actually work before the springs bottom out so it isn't the coils bottoming and stopping the suspension travel but it is the rubber bump stops limiting travel before that happens.
I would say get the springs out and compare to what they are supposed to be for coil length and wire size. if all good then get another set that is rated for more poundage. if you have a vehicle scale somewhere close you could weigh the unit on the front axle and get springs accordingly.
there is also the air bag route but that is a whole different kettle of fish and requires different lower control arms possibly, as well as a compressor, different shock mounts, etc.
there are also air springs that are made to fit inside the coils. they get filled up as needed to level the truck and, as long as there is no leaks, they stay at that pressure. that also requires the shocks to be moved outboard of the coils.
much better to get a spring set that will work
that style of spring adjuster would be hard to adjust in this scenario due to access