I live in the Lowville area, which is father north than you and my 1955 uses the same 3 EH batteries. as long as the starter is in good shape and the batteries are charged properly the tractor starts well. I don't know if it is true for the newer Whites, but the Olivers had two differnt starters. The one turned the motor over a lot faster than the other. The high rpm starters will start a tractor a lot better in cold weather than the low rpm ones will. I had one of each. The 1955 was a lot tougher to get fired up in cold weather with the low rpm starter. As far as the choice of batteries goes, the cold cranking amp rating would be the key, I would think. If you could figure out a way to make two 12 volts fit into the tractor with more cold cranking amps than the 3 Eh's would have, it might be worth the effort.