The springs from SD are designed as load helper springs to keep the correct ride height with heavier loads, not as "lift" springs. Since you are not adding weight, the static ride height will raise.
The kit from Supreme seems to be well designed and priced, and will probably give you the lift you are after.
For the front:
My concern with either methods is still operating the suspension at the extreme end of its travel. Dropped or raised spindles change the spindle pin height to raise or lower the vehicle, but maintain factory upper and lower control arm angles and ball joint angles. For some applications there are also control arm kits that raise or lower the ball joint location to change the height, but they still center the ball joints in their travel at static ride height. A good rule of thumb is for the suspension to be in the center 1/3rd of suspension travel at static ride height. When your static height is in the top or bottom 1/3rd's, it changes the angles of the control arms, so you tend to either hammer the bump stops, top/bottom out the shocks, and run the ball joints at the extreme limits of their range of motion, which causes either early failure from wear or breakage from binding. I mention hitting the bump stops often, and while it may seem as an easy solution to simply trim or remove the stops - not advised. The stops are there for a reason - to protect the shocks from topping/bottoming out and to protect the ball joints from being damaged from binding.
Another issue with lifting a vehicle. When you change the spindle pin height or use different control arms to change the height, the spring rate remains the same, so the loads on the control arm bushings and ball joints also remain the same. When you install heavier springs to raise the vehicle, you also increase the loads on the control arm bushings and ball joints - again causing increased wear and/or failure.
Because alignment specs are given for the control arms to be at a neutral angle, when you change the ride height with springs, you change the angle of the control arms at static height, and sometimes it can be hard to correctly align the suspension. Also sometimes the constant hammering on the bump stops makes it hard to maintain alignments.
The rear:
Changing the ride height with blocks has been done for decades and when quality, matched parts are used is a great way to set static ride height. Sometimes the new ride height needs a shock change to keep the shocks centered in their travel at static height.
Just some friendly advise from 40+ years of 4wd and race suspension experience. Good luck with whatever direction you chose to go with the truck.
