One vote for auger. I make tons of wooden joints (with wooden pins). I use a brace and bit and the auger bit is the fastest by far for narrow holes. I would assume it would be fastest no matter what method you use to turn it.
That's a Forstener bit in the picture because the holes needed a flat finished bottom as they don't go all the way through the stringer. The hatchet and knife is how I make the dowel for the pins.

That's a Forstener bit in the picture because the holes needed a flat finished bottom as they don't go all the way through the stringer. The hatchet and knife is how I make the dowel for the pins.