In addition, you could also ensure that your OG is high enough that when your yeast poops out around 18% ABV, it finishes in the 1.018-1.022 area... or higher if you want more sweetness.
With only 12# of honey, I would normally be thinking of a 3 gal. batch or so.. but I'd run the OG numbers through Beersmith or something. If you had an OG of 1.150, and let the yeast peter out at 18%, your finishing should be around 1.018.
12# of honey in 2.75 gallons of water should get you close to 1.150 OG...
Or you could switch to D-47 which maxes out at 14%, and has a nice mead profile.
Good luck!
--LexusChris