DBCNM,
Without ferry tanks, you are not going down the central Pacific.
During northern winter, I would suggest the range you have is very marginal to go around the north.
I commend to you a very close study of the weather in the northern Pacific (even in "summer"), I think you will suddenly find ferry tanks a good idea. Even your range quoted is a bit marginal for north Atlantic winter weather.
Tootle pip!!