Talk about luggage racks and attachment continued here.
I have a Reutter rack that I kept from when I had my '57 1600S 356 Coupe. It was chrome when I had it mounted on my previous metallic Silver VS. It is now powder-coated black to match my current black VS.
Here is how I attached this rack. Click on pics to enlarge.
1) Carriage bolts
2) Nylon spacers
3) Nylock nuts
Assembled bolts, spacers & nuts on the rack as pictured below. I used a few nylon spacers I already had on hand, but you could cut your spacers for a more custom fit.
I inserted the rack down into the air intake grill, marked where the bolts made contact with the tray, then drilled proper size hole. I used small fender washers on the top-side to spread the load. The rack is just making contact (resting) on the aluminum grill to further spread the load.
Here is the view from the under-side...
I used small sections of the nylon spacer, filed them to fit the contour of the engine lid in order to keep the bolts at a right angle to the rack (for better stability and lessen probability of cracking the fiberglass).
Here is the rack attached to my VS...
...and with my accessories...
Hope you find this info useful!