So, dear framebuilders:
I have a bunch of 1980s steel frames that I would like to drill one tiny hole through the head tube lug in, to run dynamo wiring. They are:
2x 1983 Miyata 610
1x 1984 Univega Specialissima
1x 1983 Raleigh Gran Tour
...so all are fairly sturdy touring steel frames, all are lugged. And all of them have decent paint that I would rather not wreck fully.

the idea would be to drill the smallest possible hole to run a dynamo wire through, on the head tube lug joining the down tube. According to some, I should do this on the side rather than underside (anyone seconds that?).
the wire would then emerge through the bottom bracket shell (either through an existing drain hole or through a new one).

Anyone has any special advice? Any tips for minimising the impact on the paint? Any do’s and don‘ts that I should be aware of?
thank you