Nearly all pancake style holsters will do a great job of hiding a little J frame. I doubt any maker could foul that up. Personally I send folks to Galco for an over-the-counter solution in gunleather.
That said, with the very short barrels you'll either want the full hoop of the trigger guard buried in the holster (so no Threepersons method) or a thumbsnap.
You might pay most attention to carry angle of any maker you consider, though. The more vertical the top strap (perpendicular to the ground) the more forward it will want to be carried, to avoid an awkward, broken-wrist draw. With a pistol that small, with factory grips, any angle will conceal, but just any angle won't keep it at, say, 4:00 so it doesn't show with an unzipped jacket, for example.