I first added built in jack sockets using plastic cliff style sockets because I had some already and they keep the ground isolated from the Pedaltrain chassis. However these are less than ideal because the contacts are exposed and can short or get dusty. There is also no strain relief on the cables which could be unreliable for the solder connections. I found that flexing the cables would bend the contacts and stop them being in full contact with the jack that was plugged in.
Ideally I’d use Neutrik sockets with the protective strain relief covers. But the Neutrik sockets see too large for the rear panel of the Pedaltrain mini. My solution was to use the insulated plastic switchcraft style sockets which while square, still seem to fit the Neutrik strain relief covers. I was going to add a cable tie to keep it tight, but seems to be snug enough without it. Here’s some photos: