Correct wheel offset and a happy front-end

Hey,
I'm pretty much on the same page as you brother...
What I'm really trying to figure is, what is really the correct number?
Just doing the math on that 5.5" wheel, I'm thinking the offset is around +10mm. If you look at re-pop 6" rallyes, they're typically at +6mm. Other wheels, companies like TireRack want to sell you with numbers nowhere near these.
I would think as long as I stay around that +6number I'll be fine.
Again, I'm just really curious as to what the original number truly is...

Thanks for your input.