I recommend a deep threaded screw such as a #7 x 1-5/8″ trim head auger point. For longevity, 316 stainless steel is ideal for highly acidic wines such as a late harvest Johannisberg Riesling. For a higher pH premium California Chardonnay you may be able to get by with less expensive 305 stainless if you are careful to rinse and dry your equipment thoroughly after every use. However, 316 stainless is also highly resistant to salt water corrosion, an important consideration if you attend seminars near the ocean. Any variable speed drill with a 300 rpm low speed setting should be do the job. Finally, as always, be sure to wear your safety glasses, be careful, and have fun. 
Informative post, Seldom. You neglected to point out however that in North Carolina, a bonded NC contractor’s license in addition to a variety of permits is required before commencing this type of wine bottle renovation. However, LEED credits are available if wine effluent bioprocessed through human digestive mechanism is used for on-site vegetative irrigation.