I am in the process of building my 52 chevy pickup and have already put a TCI Mustang II IFS. I want to put a new leaf spring kit in the rear with a drop of about 4 inches (all the kits seem to do this). I also want the rear wheels to be centered in the wheel wells (correcting the factory forward placement). Would like some ideas/experiences from folks that have installed new spring kits and their opinions, satisfaction, and/or dissatisfactions of the kits.

First of all, welcome to the board! Post a few pics when you get a chance.
I'm not ready to tackle the rear yet so, I can't add much other than to tell you what I'll be doing for mine. I plan on picking up a Fjord nine inch rear end and installing a 4 link coil-over kit. Gives me the drop that I will want and can be adjusted.
Good luck!