Hyperlow CG is a frame that's really nice to work on, relatively spacious, yet low profile. Plus it has really nice shelving system which helps with clean routing of the wires. IMO this is just a perfect frame.

The biggest challenge that I've had was mounting the Tekko32 in the chosen orientation.

Let me start by saying that Tekko32 is pain to mount properly in any orientation, because on one side there are components (which look like tiny resistors) so close to the mounting holes, that they could be easily damaged by screwing in regular standoffs. The same can be said about the foil covering FETs on the other side. Holybro provides pieces of the same material as the PCB is made of to working around this design on the FET side, but nothing for the other side. So on that side I have used some tiny o-rings to protect the tiny parts close to the holes.

Once I have figured that, I made it even more complicated myself, as I have decided to mount the ESC so the power lead comes out in the back, and not on the side, since I was planning to route power leads through the rear of the quad. Such board orientation means that I've had to mill one of the shelving plates a bit to make room for the FC connector.

As you can see, at the end the power leads are coming out on the side, as coming through rear would obstruct the GPS quite a bit, which I haven't realized when I have started with this build. So I have at least used the side route to mount the capacitor (ziptie to the power leads near the ESC).

With the ESC mounted, the challenge was to keep the stack low enough to fit it into the 15mm space defined by the main standoffs. Plastic standoffs were not an option, as the stack would be way too high. So I decided to put everything on a single steel screw running from to bottom all the way into the top plate. I even didn't have enough space for a nut between FC and ESC, so I have again used an o-ring - this time just a bit bigger.

As a result, there's just enough space to use low-profile steel nut at the top of the stack, which touches the top plate lightly. There's literally not a single millimeter left.

The rest of the build was just a piece of cake. Should I do this next time, I would rotate the ESC by 90º, which means that I wouldn't have to mill one of the shelving plates, and the motor wires would run a bit cleaner (hidden under the shelves).