Yeah, I had planned on using at least 6 pins, but ended up being able to only pass through 4 wires. The idea was to be able to use more than a pair of wire to pass through the current. You're saying 5A? That seems so little! I'll have to monitor the connector's temperature under load.I see you used GX12 connectors? Unfortunately they're not much better or even worse (the cheaper ones are mostly rated for 5A only) ... the normal barrel connectors that come with many PicoPSUs are completely made from brass and can at least conduct some heat to the case, the GX12 can't because the PINs are embedded in plastic for insulation... so depending on your continuous load you *could* run into some issues here...
To be on the safe side, personally I'm always using XT60 or XT90 connectors for higher wattage 12VDC applications.
I didn't want to use anything but a round connector, that's why I went with these.