A lot of dis-information. Right now I'm in the middle gaining approval for the new GE turboprop to burn S10 Diesel In Brazil
, that is a USLD (10 PPM) of sulphur with a 5% bio component.
By specification Bio can be either animal in origin (rare) or vegetable, soy and palm oil being very common.
Regular ole #2 Diesel is gone from the US, you can in theory get Diesel up to 1000 PPM sulfur if your a cat 3 Marine engine, but surely none of us are and I believe you have to prove your emissions are low, to get it. And they are after the big ship engines to reduce emissions as well.
From a lubricity perspective not much beats a 20% mix of Bio, just it's hard to find, and I do not know, but suspect it may be more likely to support biological growth (bugs) in your fuel tank
Bio is not compatible with any brass in your fuel system either, somehow the brass changes the chemical make up of the fuel? We are having to eliminate all brass from our fuel system and and we have a lot of it, all drains etc are brass.
If I could get it, I'd run old #2 high sulfur Diesel, whatever you run, use an anti-microbial additive, I've had good luck with Biobor jf. I am sure there are many other fine ones.
It's actually the ULSD that has caused problems with some rubber components in older engines, but one problem with bio fuel is it essentially has no standards, try looking up the ASTM standard for bio and see what you find.
The ASTM for Diesel fuel is D975 I believe