1/8" is plenty

Tmac, are you running the stock steering box?

Use my old trick to massage a header tube while the header is bolted in...
Take a piece of sheetmetal about 6" long by 2" wide.  Fold it in half so you have two leafs each 3" x 2" wide.  Insert the sheetmetal contraption (I just love it when the talk gets technical) with the fold downward between the header and the box.  Then get a 1" wide wood chisel and drive it inbetween the folded leafs of the sheetmetal gizmo.  The chisel's taper will force the sheetmetal outward, and when you get through, you will have a gap as wide as the thickness of the chisel plus two thicknesses of the sheetmetal, less a small amount of springback.  That way you can move the wall of the header tube without actually hitting the tube with a hammer.  Remove the apparatus before driving.

And why in the heck would Patriot sell a product that does not clear a stock steering box?  Sounds more like something HOOKER would do, and charge triple for it.