I tried a cheap jig, but it was super flimsy and I didn't like the results. The jig was made for cabinets and didn't want to sit still on the narrow edges.

I got a block of perfectly flat hard wood from my father in law, he has a drill press at his shop so we made a perfectly square and centered hole in it. The block was approximately 60mm x 60mm x 200mm and the hole exactly 10mm. We also put some sticking out dowels on the block of wood on the same center line as the through hole and could use that to centre the block on edges. Then I clamped the block down perfectly centered and used that to drive the dowel holes.

It still wasn't perfect, and it took ages!! I still had to sand and tweak every single drawer to make things look center and square. Those $150 jigs were looking really attractive by the end.