I would go for the Erwin bits myself, then put an extension on it to drill deeper.
the auger bit with a single cutting edge will tend to wonder off really quickly especially in old solid Oak.
them Erwin bits with a good 18volt battery drill on the lowest speed will pull themselves through the timber.
DeWalt do a good set the same design, three cutting edges rather then just one.
i use them all the time with my 18 volt drill, 32mm on the lowest speed, they feel like there going to pull the drill out of your hands.