Just finished building my new Mein Enigma kit, #75, which I've had on my shelf for some time. I'm waiting on some replacement parts to fix a couple minor problems but I've got it working for now. Very nice kit, well-designed and great documentation.
Anyhow, the docs pointed me to the web site and I've been reading as much material as I can. I've PM'd the U-boat adoption coordinator directly, but no reply yet, so I've just gone ahead and appropriated U-709 as my U-boat. I've used the Enigma to encipher a short test message. If anyone wants to see if they can decode it, I'll post it below. I used the M4 Advanced procedure and the 2019 documents and tables, as I couldn't find any 2020-dated materials. Hopefully, I've done it correctly :-)