After some more sawing, screwing, connecting and cursing I can now show some pictures of the finished hardware.
The tube in the background has a slight kink, but that doesn't obstruct the flow passage. I'll try to remove that later with a hot air gun. As it's a teflon tube it is quite sturdy and really doesn't like being bent, but I couldn't get more flexible silicone tube for high temperatures in reasonable amounts or at reasonable prices.
More about the electronics box below. The terminal strip that connects the heaters to the electronics box needs a cover, but I'm not yet sure how exactly that should be done.
As the thermocouples are fixed in place with silicone (in the chamber), I made a small bracket to stabilize them. The upper thermocouple got loose during assembly so I had to attach it again, and the silicone needs some time to cure. No testing today!
The chiller is mounted with another bracket, and has a thermocouple at the outlet. I'm planning to use this to measure the amount of excess evaporating galden. I'll write more about this when I did some testing as I have no idea about how well the system reacts.
Top with opened lid
The clamps swing away to the side to release the lid.
Lower (high voltage) PCB:
Silicone mat to isolate between lower and upper PCB:
Upper (low voltage) PCB:
In the left view picture above you can see a small hole in the lid, which is above the Teensy LC's programming button. If nothing breaks I won't have to open the box again until I have to repair or change some of the electronics.