I found a 28" gun at Jaqua's for my conversion to the Galazan 410 barrels. It hadn't been shot by the previous owners, that I could tell. I used the 28ga 28" barrels a bit while waiting for the 410 barrels from Tony. It was whippy, but manageable. Although I'm pretty good with 26" barrels, I prefer 28" for my blindfolded shooting.
Or at least it sometimes seems like I'm shooting blindfolded. I would not trade my 28" bbls for 26".
My recommendation would be to find a gun with 28" barrels and then have the triggers converted.