I know what I'm going to do.
I'm going to use Automotive JB Weld, bar stock aluminum, and screws.
If you look above and below the heatsink in the photo, you'll see holes for a total of six screws: two top left, one top right, two bottom left, and one bottom right.
I'm going to attach four pieces of bar stock aluminum to the heat sink using JB Weld. I'm going to drill holes in the bar stock that align with the screw holes. Then I'm going to use screws to mount it to the holes.
I really don't want to drill the heatsink, as that will affect the placement of additional LEDs in the future (and I'm not so good with a drill).
I'm waiting for more stuff from Martin, so the LEDs aren't done yet. I wonder how many orders it takes to get everything one requires? I keep finding more things that I need/forgot. I'm sure three will be the charm.
Will any hardware store carry the bar stock? What is it normally used for (so I know what department to find it in)?
Edit: in tearing the hood apart I sure learned one thing . . . JBJ's quality control and manufacturing standards are abysmal!