Here's a possibly-interesting follow up to this thread.
Based on other's experiences and recommendations, I decided to try making my own "click-bond" style standoff mounts and experiment with different adhesives and surface treatments. I didn't take pictures before hand, but I'll attach a picture I took this morning after some pull tests and re-attaching one fitting for further testing.
Methodology:
I tried four different types of attachments, three adhesives, and two surface treatments. I have not yet tried all possible combinations. This was not a particularly scientific test, but I did make an effort to make my process as consistent as possible. I did not make any attempt to measure the force applied during the pull tests.
Attachments:
1. Homemade attachment made by:
a. cutting a 1" square of 0.032" sheet aluminum from kit scraps
b. deburring and rounding edges
c. drilling #19 and dimpling a hole for an AN509 screw
d. installing an AN509-8R8 screw with flat washer and nut
e. installing a second nut to use to grab the screw
2. Random nylon (probably) 4-way cable tie with double stick tape (factory applied) from an unknown vendor (I got these when I bought my tail kit from the previous owner and he included a bunch of stuff and supplies)
3. Nylon cable tie from Aircraft Spruce (Tyton brand)
https://www.aircraftspruce.com/catalog/elpages/hellermann_tieanchor.php?clickkey=134587
4. Stainless steel anchor from McMaster-Carr (29/32" base 1" long #8-32 screw thread, "Rotaloc" brand)
https://www.mcmaster.com/97590A838
Adhesives:
E-6000
Gorilla Glue
JB Weld "Plastic Bonder High Strength Structural Adhesive"
The random double stick foam tape that was already on the 4-way nylon tie mount.
Surface Preparations:
1. Bare aluminum, cleaned with acetone, scruffed with maroon scotch-brite, then cleaned again with acetone
2. Aluminum coated with Sherwin-Williams strontium chromate primer, CM0724400, yellow, spray applied after scuffing and cleaning with acteone, fully cured, wiped clean with paper towel soaked in acetone (primer was not removed, only wiped).
3. In all cases except the double stick tape, the base of the attachment hardware was scuffed and/or sanded to apply "tooth" to the bonding surface.
I bonded each attachment type to both types of substrate (except I only applied the double-stick tape mount to the primed aluminum). I allowed each adhesive to cure for the recommended time at ambient temperature (shop was 68F when applied, overnight shop was allowed to drift down to 50F, then back up to 68F when tested). The E-6000 was tested prior to its full strength cure time (24 hours) because I was impatient. I'll repeat this test with a full cure time just for completeness later.
After curing, I pull-tested the various attachments in one of two ways: for the screw-type mountings, I threaded a nut onto the threads, then gripped the nut with a pair of Vice Grip pliers, and pulled, first in the direction normal to the aluminum surface, and then, if that did not fail, with a "peeling" moment on the screw shaft.
For the wire tie type mounts, I threaded a locking Nylon wire tie through the mount and then pulled in the normal direction--again if that did not fail, I pulled at an angle intended to try to get the adhesive to peel free.
Results:
The 1" aluminum base homemade attached with E-6000 adhesive pulled free relatively easily in the normal direction in all cases. I will repeat this test with a full 24 hour cure time at a later date, but I'm not encouraged by this result.
The nylon "Tyton" wire tie mounts bonded with E-6000 pulled free in the normal direction relatively easily.
The "Tyton" mounts bonded with Gorilla Glue pulled free in the normal direction with a little more force than the E-6000 required, but still not enough for me to feel comfortable that it would be at all permanent.
The "Tyton" mounts bonded with JB Weld Plastic Bonder held relatively tightly but still pulled away such that it would not be permanent. I expect this is primarily due to the small surface area of the Tyton mounts.
The 4-way wire tie base with foam tape applied to the primed surface held very tightly in all pull directions. I was unable to pull on the wire tie hard enough to either dislodge the base or to distort the underlying aluminum.
The "Rotaloc" mount attached to the primed surface with the JB Weld Plastic Bonder held so tightly that I could not pry it loose even with a peeling motion without severely distorting the underlying metal.
I am in the process of testing the JB Weld Plastic Bonder with my homemade 1" base mount--when it cures and I test it I'll post those results.
The JB Weld Plastic Bonder is not equivalent to the normally used JB Weld--it is advertised as specifically intended to allow bonding of plastics and it cures with a flexible quality, not rock hard as other epoxies do. It seems very durable so far.