The PCB has been manufactured by DirtyPCB (along with the 10TFF modules) and the results are pretty nice :-) I should now test the solderability but I don't worry about it. I'll use these boards for soldering workshops.
Soldering was a breeze and 5mm LEDs also work instead of 3mm LEDs (I should add a polarity sign to the LED though). The circuit worked right away when powered on !
You can watch a video there : https://www.facebook.com/YGDES/videos/1131949946899923/