Re: rear up front questions?
Typically, putting rear springs up fornt will give about .75" extra height on the front end, this would be in SPUA form.
For SPOA though, the overload leaf in the back adds close to .5" of lift that the front never sees. In this way, moving the rears up front makes the vehicle sit pretty close to level. If the springs are all in equal condition, you'll likely notice no visible difference in lift height front to rear.