Ok, I'll the one to say it AGAIN.
Forget about the drilling; get an oiler and drill it any way you like. It's the ball, the surface that matters, ESPECIALLY in this case. Get one of
Lane#1 Super Carbide Bomb,
Columbia Throttle,
Track Phenom or Mutant,
Visionary Midnight Scorcher,
Brunswick Swamp Monster,
Hammer Vicious or Diesel Particle solid,
Ebonite APex Addiction.
Then drill it anyway you're copmfortable. With heavy oil the actual drill will make little difference, unless the actual ball is not really strong enough.
One of the strongest earliest rolling drills for a true oiler is a pin at leverage (3 3/8" from PAP) and CG on PAP.
If you can't make one of the above balls, sanded to 400, drilled as suggested above, hook on any legitimate oil pattern, then ....
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"Those who do not remember history are doomed to repeat it."