Glad to help out, Vanagoner.
In colder climates the winter diesel fuel or D1 is in effect kerosene
Nope. It's possible that you have some information that I don't, but as far as I am aware, here's the score: A lighter diesel fuel is used, and larger proportions of kerosene are blended; some areas do use the name D1 / Diesel #1 to refer to kerosene / jet fuel variants, but as far as I know, on-road diesel fuel is never more than a 50% blend of kerosene. That's important, because straight kerosene can (Not that it will, but can) wreck things in very short order. Its lubricity is dramatically lower than diesel fuel, and it is flatly not recommended for use in normal applications. Special low-lubricity components do exist for use in military applications and stuff where jet fuel / kerosene is what will be used, but even with those components, the pump wears out way faster due to super low lubricity.
Gotta agree with you on the B50. Unless you have some form of tank heating, or a secondary tank with heating, or something along those lines, I would not recommend anything over B50 in continuously sub-zero temps. I've personally experienced gelling at low temps with B50 blends, and basically had to go easy until the return fuel heated the tank, pump, etc. If it had been a little colder, I'd have been euchred.
Slave2school:
(Just realized that Bigblockchev has already said a bunch of this - I'll leave it here, but take it as agreement and elabouration. :-) )
No ratio of kerosene / Biodiesel has been "proven" safe, because so far as I'm aware that testing hasn't been done. I don't personally know how well kero blends with B100, what it does to the lubricity of the biodiesel, etc. Since kerosene is more expensive, pretty bad for your pump, and more hydrophilic than diesel fuel (at least as hydrophilic as B100), I don't see any real advantages to using it, other than letting you run B100. I'd be more inclined to drop down to B30 with the rest petrodiesel rather than B50 or B60 with the rest kerosene, based on price, longevity, and (anecdotal) evidence to support its reliability. That's me; I won't tell you that it won't work or that it can't, I just don't have the data to be comfortable making the decision or making a recommendation at this point. From a practical standpoint, I think that in the absence of a heating system, scaling back on the biodiesel proportion is the cheapest, easiest, and lowest-maintenance option for a couple of months of the year at most.
Bearing in mind that I live in the GTA part of the time and in very rural central Ontario the rest of the time, so -20C and below is not foreign territory - our climate is classified as "sub-arctic". In even slightly lower latitudes, none of this applies.
There presently aren't any real winterizing additives made specifically for biodiesel. Again, the market is sufficiently small that nobody really cares. The most effective "winterizing" method I've heard of is freezing cans / jugs of biodiesel to a given temperature (in your freezer, for instance) in order to solidify it. Usually, a portion of it remains liquid; you pour this off, recording the freeze / cloud / cold filter plugging point on the container. This is largely unscientific, but it gives you an idea of the temp. The solidified stuff can be thawed and re-used as "summer B100" and the thinner portion can then be stored and used as "winter B100" down to the temps that you observed when freezing. It's a reasonably good system, and considerably better than blending, given the choice.
