As mentioned the shackle swap and hangar flip combo will get you in the ball park of 4" as well and keeps the axle under the springs so not need to modify it swap it. As long as you use a good grade 8 bolt when mounting the hangar back to the frame, it's just as safe as when it left the factory.
Shackle swap/hanger flip combo moves the back end of the springs up about 4", but as the axle is a little forward of center, you get about 2" of lowering - OK, for "leveling", not really lowering. The good part is - it is quick, easy and if you don't like it, you can reverse it.
You can also replace the Ranger rear hangers with Chevrolet Silverado hangers and get another couple inches, Chevrolet hangers are considerably below the frame, but that requires drilling some holes in frame to mount them.
Given the cheap steel the Ranger frame is made out of, grade 8 bolts are overkill. But this is suspension and price delta between 8 - grade 8 bolts and grade 5s is only pennies. (I used 4 pair of the bolts Ford mounts the hangers on OEM but they were lying in the bucket of spare parts.
Front hanger swap/flip raises front of the spring something crazy - like 8"; almost 5" at axle and has a dramatic impact on pinion angle. It destroys the ability of the truck to function as a truck, IMO.
Personally, I would the rear hanger swap just to see what it looks like before I spent real money on springs - then you know exactly what you want.
Also, I wouldn't go more than 3" on front springs - you're losing to much travel. If you want more its time to change to the DJM arms, again IMHO.