Just use a hand drill? Slightly undersize and then ream out until big enough? Tuner holes normally aren't that tight a fit. The tightest fit is on the rear of the headstock and the hole on the face of the headstock is normally quite a lot wider than the screwed barrel. As long as the centres are in the right place, it should all look fine. Whichever way you go in, just attach some flat scrap wood to the other side to prevent splintering when the drill goes through.