[gopher]

.. where you can buy the fittings for our holes?

If you want to DIY the whole project - find some small metal tube and buy the correct sized metric hex head bolts. Clamp a bolt in the vice, drill a hole the same dia as the tubing a mm or so into the head and then a smaller hole all the way through. Cut tubing to length and braze/solder/epoxy together. Not pretty but it works.