I don't know about HOB options, but I'm currently building a 80/20 light mount for my new build. I was trying to solve the same problem because I would like 4 Lumen Bars. I know the nuts on top of the bar are M3 so my plan is to mount a ball latch to the the top of lumen bar and connect it to the aluminum t-slot. It would be simple enough to the Kessil pendants to the 80/20. I will know if my plan works as soon as I make it to the hardware store and pick up M3 bolts.
The mounting HW I plan to try.
These items are 100% compatible with the following manufacturers: 80/20 #4487 or 65-4487 TSLOTS #671032
www.tnutz.com
My backup plan is just use M3 T-nut with double threaded m3 bolt. The reason this is my backup is I would like to be able to angle the light and can accomplish this with the ball latch.