I'm down below you in the southern triangle, South Carolina. If you look way at the southern tip on a map the dot for beaufort will jump out and tweak your dulcimer.
Its difficult to say. It all depends on how the grill will be set up. If your going with a basic horizontal or verticle bar grill on your truck and you take off all of the original grill a 1/4" with .65" wall flattened a tiny bit giving it two sides but a rounded apearance and form it into the original shape of the grill and make a thinner bumper it would look sweet. Now if you were to just remove the virtical bar and left the hood trim bar and the horizontal bar, using semi flattened 3/8 would be fine because any smaller and they would look out of place do to the thick horizontal original bar. If you were to add some verticle flames to a horizontal bar grill I'd use semi flattened 3/8" for the flames and 1/4" for the horizontal bars so they would fall into the background. by adding a clear black light activated paint to the anodized or polished grill you could make them glow at night or just anodize the flames and leave the horizontal bars polished or brushed. It all depends on the grill type about the size of tubing used, but never use totally round tubing, it looks tacky do to the fact nothing else is 100% rounf other than the wheels. The spacing usually is double what the original diameter of the tubing was. For example ever 1/2" for 1/4" tubing and depending on the amount you flatten, it usually turn up near 5/8-3/4" gap so on so forth. If you'd like some help on the design or anything else you know where I am.