Radiator support might not be needed, but you're already welding. What's another day of mock up and welding? I'd also suggest having the Kmember seam welded and reinforced. I think u said you're running QA1 uppers and lowers, otherwise I'd say lower control arm reinforcement also.
My factory K-frame is fully welded and has a few minor mods to clear my oil pan. My radiator support is 2x2 box with corners notched for radiator clearance, nutserts installed for mounting the latch support brace (look at center) and brackets welded for the lower valence attaching points on both ends. I bought a kit... would have been just as well not to. It was a little wide and would have hung down really low, it would have been visible and I didn't like the way it would look. I had the guy doing the fab work section it to the right width and tuck it up to the same height as the factory piece, then had him make notches in it to clear the radiator. It also serves as an extra handy point where I can lift the vehicle or place a jack stand if needed.
Here is a picture during fabrication:
After paint:
Latch support and valence bolts on to original locations and the support cannot be seen when the lower valence is installed.