Got the other side done this morning and finally got to take a test drive with them (
the flicker is my phone camera - they are lit solid in person)
Again, THANKS everyone for all of the help and motivation to get these done - I had been eyeing these for almost TWO years on Aliexpress.
I tacked the LEDs in place with Gorilla Glue GEL as it's THICK and once that cured, I used JB Weld all around the joint to glue/seal the LED's in place. I used the JB Weld as it came with a EZ mix nozzle so I didn't have to mix the epoxy or make a mess. NOTE: Goo Gone will clean off any JB Weld that you might get onto the cap as long as you do it immediately - ask me how I know!
The passenger side cap was a little tricky to mount on the mirror housing but the driver side cap was a major PITA to get fitted. These are replacing a OEM VW matte chrome Golf R set of caps and when compared next to each other, the Chinese caps DO have slight dimensional differences vs. the OEM VW ones, so I'm sure that played a part in the fitment issues.
Chinese on top, OEM VW on bottom
Chinese on left, OEM VW on right