Based on thorough reading on here and other sites, here is my conclusion on "leveling". My goal is a slight bit of rake, so there is less gap in the front fenderwell than the rear. With this done, the running boards and roof line are level. With equal amount of fender gap front/rear, the running boards and roof line would be higher in the front than the rear, this is not the look I went for.
That said, here's my suggestion to anyone looking for the same as me. If you've got a v8 4x4, go with the FJ springs all around and 1/2" thick spacer. If you've got a v6 or a 2wd, go with the FJ springs all around and the 1/4" thick spacer. The V6 models and 2wd models have less weight in the front end, and when you do the FJ swap you gain more lift than those with the v8 4x4's. I've started a little study on this and done calculations to approximate how much lift was given from just the FJ springs with each configuration. See
this thread for a summary of the info I've gathered from members. Also, if you've done the FJ swap, please post your info there.