Were you able to math out those legs as being better? I wasn't able to get the spreadsheet to work out any real use for the ice legs over otronif or R15 Manibozo
ItemSet 315421
Hands have DA+2%
All Manibozho are R15 STR
Things I tried to change -
Ammo for Honed tathlum
Legs for Ice Legs, DA otronif
Waist for Anguinus Belt
Body for Thaumas, Otronif (DA+2%)
Head for Whirlpool (wins with impetus down)
But this set seemed to work best for Delve fodder/Tojil with at least haste, focus, Impetus.
Edit: Because of annoying forum trolls, I redid this with all buffs spreadsheet can do in all possible combinations, including cor/brd buffs, and never found a situation where ice legs were better.