I would say that stainless is fine, even tho more brittle, they are so damn big to begin with doesn't matter....
I will say if you use stainless bolts anywhere be sure to use neversieze, grease or something them, stainless bolt and nut put together and tightened good will almost always gall the surfaces together and never come apart without cutting them or breaking them......Corrosion isn't needed to make it happen, it's instantaneous......I run into this all the time when these lineman bolt leads to big Xfmrs and Breakers without using it. When testing this apparatus I have to disconnect it. Usually involves a sawzall or a 1/2 breakover bar, cheater pipe and enough grunting and sweating to break the bolt in two by twisting it far enough to break:bang head:.......
A stainless nut or bolt by itself, threaded into some other type of metal will almost never do this..