Very nice. Nice to see some 'out-of-the-box' diy. most 'out-of-the-box' solutions nowadays is just to throw a 'chi-fi' dap at the solution. In the low-mid 2000s, this site had a good combo of diy'ers. Now, it's a good amount of posters focusing on their on 'brand'. diy has taken a back seat.
Anyways, I did something similar before moving on to the a Gotham USB (5 layers of shielding); but I use it for power only. No data soldered on the Gotham. It's mainly used to power a Raspberry Pi. I did not though consider wrapping the ferrites in tape, well-played. It was a pain having the ferrites roll around.
On your next Amazon order, maybe give Faraday tape a try?
https://www.amazon.com/TitanRF-Faraday-Tape-High-Shielding-Conductive/dp/B07CRLCGCH/ref=sr_1_4?keywords=faraday+tape&qid=1580413500&sr=8-4&th=1
That's what I used to wrap a USB cable before moving on to the Gotham. Not sure if much difference with Relectix. I believe Relectix is to block out sun/UV.
I wanted to try lining the inside on the Mojo with Faraday tape, but my 2nd hand Mojo buy here ended up a dud. Not sure of the heat-generation though...
https://www.head-fi.org/threads/crinacles-iem-ranking-list.857498/page-125#post-15030289
Your really going to make me wrap a ferrite around the dongle now w/ tape...
It does work though as I blocked off a small portable router on all sides. Then I tried removing side by side until I got a SSID signal.
Anyways, nice to see some experimentation ...