ty,
and hm no, look:
the most people would soc a Lo-rune, but:
Lo for example would be only + ~14% chance for double dmg on a barb
but WHY 40/15?because Fools weapons got a bad base dmg in general
and as I use Highlords more DS ain't really necessary, i prefer to have higher base dmg tbh
also 40/15 is the highest possible dmg from all jools/runes I found
ETH rune works actually fine as well. It is less dmg but more hits in average
Ber Rune works too, but it's less effective with every hit you make.
that's my opinion at least

Did you do the math? There's really no way to have an opinion - either Lo is better or it's not. Your jewel adds 14-53 damage to your sword, and I think that a ~14% crit chance is better, but I can't tell you without seeing your stat screen. Ber or Eth are probably better too.