Getting new wheels. Offset question?

['04excursion6.0]

I have a 2004 Excursion with stock suspension. I'm looking to get a set of Fuel Krank 18x9 wheels. They come in either 4.5 inch backspacing (-12 offset) or 5 inch backspacing (1 offset). I thought 4.5 inch backspacing was proper for a 2004 Excursion but when I put my vehicle info in on all the websites they say the 5 inch backspacing is for my vehicle.

In terms of tires I'm thinking about Nitto Dune Grapplers 285/65-18.

As far as I know this set up will fit without any problem, I'm just not sure which offset to go with. What do you guys think?

Also what finish do you think would look best? Black, silver or chrome? My X is mineral grey metallic.

[JFLemm]

4.5 inch backspace is correct is my understanding.....