Found this
deal on Amazon -- six gallons of Delo (227808497-6PK) Extended Life Antifreeze/Coolant for $163. Doesn't seem half bad.
THIS PDF verifies that it does indeed meet B1 Type III specifications and it is free of nitrates, borates, silicates, phosphates and amines ... rated for 700,000 miles or 15k road hours.
What are we all using in our T444E's? Anyone using a cheaper option out there?