Hi Darren,
Yes, for straight D pipes I have it pretty much set. But my ceramic pipes sometimes are not the same length after the first firing, and often I don't use a diatonic scale. In PVC, I just mark them and drill. Like you said, take a couple of minutes. But even then, a little bit of careful undercutting wth a file, tuning them with an electronic tuner or keyboard, and a final polishing of the holes and surfaces - can improve even a good flute.
And of course, since I don't have a drill press or even that kind of work bench, a lot of things that are easier with jigs and such are not for me. Yet.
Welcome to the forum, hope you enjoy it and we would love to see your setup.