Vedder pocket locker here. J-frame is only a pocket or ankle carry for me these days, but I have used a Garrett Industries Silent thunder in the past for a steel 640 IWB. If I'm IWB carrying, it's a G19/43.

Good luck, lots of good things with a J-frame. My 340PD and 442 are pretty dinged up from carry but it's not a show piece, nor will they be sold.