Thanks for the responses guys. After further questioning everyone on the planet, it sounds like when it comes to these systems it is really up to personal preference with respect to ride stiffness and suspension travel. The recommended installed height ranges from 5" to about 7" depending on who I ask (I even asked the local minitruck/stereo/window tint/espresso emporium guy

). What I have decided to do is basically the same thing I would do with coil overs and that is to build some mechanical adjustability into my mounting system that will accomplish the range of installed heights at my desired ride height.
A question for Tony; The bags you say you would use are lighter than the ones I have. What is the impact going to be of using the 2600# bags out back vs the 1500# units you say you would use? The front bags you said you would use are close the ones I have (2400# vs 2600#).Oh yeah, forgive my ignorance but 1:1 ratio with a 4 bar??
Some particulars on my truck: 70 blazer, mustang II front susp/tubular a arms, standard small block, 4 link/wishbone rear, sway bars F&R, tube frame front & rear.