I'm tractor shopping at this point, but have had some past experience with equipment. I have also wondered about winter fuel recommendations, so I am glad to see this post here. I hope we get some more response on the subject.
I'm not sure the two previous posters made it abundantly clear, but it is my understanding that #1 fuel oil is kerosene, and that jet fuel is also kerosene, with some different additives and a higher price. Someone please correct me if there is anything wrong with what I have just said.
One time on a cold winter Sunday, I was having trouble finding a local source that was open for kero for my garage space heater. I went to the local small airport and bought 5 gallons of jet fuel. It worked fine. Their nozzle was a bit large for filling a 5 gallon can, but they filled it up cheerfully. (You can probably get better service at a small airport on a slow day.)
A friend, who bought a Kubota this fall, was talking about running kerosene in it in the winter time. I told him I was a beet leery of the idea of running 100% kero.
One of my Dad's old International tractors had a "multi-fuel" setup. The W-6 Owner's Manual recommended draining off the top of the oil once a day when running kero, because some would leak by the rings and thin the oil. The tractor had two oil check/drain taps on the side of the oil pan for that purpose. I believe you were supposed to do that draining and refilling in the morning, after the oil and kero had set still overnight.
I agree with the thought that a blend would be best. I'm not sure of the proportions, but the suggestion of 25% sounds reasonable. I would think you would want to keep the oil change interval short when running kero, though. Of course a modern diesel probably has much tighter rings than the old gas/multi-fuel W-6!
Dennis