They finally switched back to summer fuel around here, which I am happy about!! Not sure if the lubricity changes with it or not however.
Anyways, I always use a low blend of quality bio in my old diesels for lubricity. On my 84, I have an aftermarket 2 micron filter/seperator for added peace of mind. I run Howes during the winter with an even lower bio blend. Or I will run 2 stroke oil or ATF anytime a year, provided that I get it for a good price. It always boils down to price, I will always run something, but always in conservative amounts to keep costs in check.