Ok. So I decided to go ahead and mount the HD rack I had instead of waiting till I could afford one of Will's (CycleOps) Grade A racks and this is how it went.
Laid down some painters tape.
Put the rack on and marked it after measuring the distances from both sides, top, and bottom. Notice the bungee cord to hold it in place while I marked it.
Drilled and elongated the holes for some fudging room. Just used the drill bit to elongate the holes by putting pressure sideways. The plastic cuts fairly easy but not too easy.
Notice I used some risers on the legs. Also, instead of grinding the legs, I just put them in a vice and bent them slightly to angle correctly. The risers also puts the rack high enough to make it easy to clean underneath the rack.
The risers ended up being perfect for this application. They have a very large footprint so the weight is distributed much better and they have a nice rubber foot pad under them with the corresponding washers of the same size underneath.
I had to buy some new stainless bolts because this rack turned out to have metric threads. Probably a Chinese HD rack knockoff.
The risers can be purchased many places but I bought them from here
. I'll be putting a bit of clear silicone inside the risers to seal them from the little bit of rain we get here or when I'm on a trip.
All in all a very simple mod. It is kinda weird drilling down on the top of the trunk knowing there's no turning back once I drilled the first hole.