aprayinbear, I would definatly HT. What kind of resources do you have?
Coal forge, propane forge, large vertical tank for oil?
If you do HT it, I'd just heat up the face, about 2-3" deep, do a dull cherry red (non-magnetic), and then quench in vertically in oil. Temper immediatly to either a dark gold to a light blue. Dark gold being harder, than light blue.
This is justmy opinion, I have never HT an anvil, but will be this summer.
Wait for someone who really knows what they are doing to answer this. Or go look up chuch robinson anvils, and send him an e-mail on how he does it.