Adding Lubricity to Diesel Fuel

I have a 2001 Dodge CTD 2500 and a friend and his son also have similar
vehicles (different years, but 24 Valve).

I have been adding abouT 5% biodiesel to my (low sulfur) fuel for
lubricity. My friend's son said he adds ATF for lubricity. Seems like
ATF is much more expensive, but how much do you need?

Also, is there a value in adding a small amount of gasoline during
winter to prevent gelling? I saw a post where a fellow put in about 1.5
gal of gas before realizing his mistake, then filled up with diesel.
Responders said not a big deal, they do that all the time.

Comments welcome!

Thanks,

Charles