Bob, barrel is holding up fine, but only a few dozen or so shots of steel through it so far. Don't foresee an issue, this is just an occasional day of play, my diehard waterfowling will still be with the old 870 - and I've only shot one barrel out of that gun in 20 years.
I can't see needing special steel wads, the ones I've got are full coverage, pre slit all the way down and seem to work fine. Certainly kills. Pretty tight pattern, too, more than lead without a wad. Moot point anyway, only wads I've found in 16ga in a year of looking! I do need to pattern them with lead for turkey hunting, I think they will help greatly for that.