Here's a look at how I fastened the bumper bullets to the smoothie bumper. I made some small threaded tabs and marked their location inside the bullets. Then I drilled two slightly oversized holes for the 1/4-20 fasteners that attach on either side. Mocked up the final location by threading the fasteners into the tabs and then set the bullet down in place. Used the MIG to tack the tabs to the bullets then removed the assembly and TiG welded the tabs more securely.
As you can see, the tabs draw the bullets down firmly in place and provide plenty of clearance for the backside of the lights. Found the correct pigtails for the 899 halogen lights on eBay and got them on the way. Still a long way to go before wiring, but that should give me more than enough time to misplace them.