Here is my experience with installing my C5.
Received it in Australia within a week of ordering, excellent, well packed, no damage and delivered by DHL on a Sunday!!
Got it going on the bench, no issues, other than firmware on the C5 does not appear to be the latest, I posted a comment on a post to get some advice from the suppliers.
I'm using a 128Gb Samsung Evo Plus SD card, formatted with Fat32 partition using EaseUS partition master - trial version(free for the moment). See forum post on details of how to do this.
Installation is a bit fiddly and it took me about 3 hrs to complete.
The camera was mounted on the left turn indicator, I had to loosen some of the fairing panels to route the cables and secure them using cable ties.

Power supply Installed under the riders seat using Velcro and cable ties.

C5 Installed under the pillion riders seat.

I used a cable tap sourced from Jaycar in Australia to splice the trigger wire onto the tail light wire. The battery wires were crimped...The objective was to have minimal changes to the bike with a neat installation.

I had a quick ride (20Km) and I got some footage following the install, although the C5 seems to have locked up about three quarters of the way. I was getting an SD card error when trying to read the files using the Iphone App. I removed the SD card C5 installed it on my PC (Windows) and was able to read all the video footage that had been recorded. Quality appeared to be good. I need to spend a bit of time to look at why the C5 did not record the entire journey. I did have 5min loop recording, I have reset the system to factory defaults to see if that makes any difference. Any pointers as to what I should do would by much appreciated. The latest firmware may solve this intermittent lock ups I hope!!
Very neat installation.
Can you take a close photo to see how the camera lens mounted on the light? that will be a good reference.
As you mentioned, please keep us updated after make default factory setting and riding.