I carry a 342 in my pocket every day. It is a little lighter then the 642. However, if I had it to do again I would go with the 642. The 642 is a lot less money and not significantly heavier.
My pocket holster is a beat up old Uncle Mike's, and I mean beat up. I have tried more then a few high end leather pocket holsters like Kramer and K&D, as well as, the soft Desantis Nemesis. I like the Uncle Mike's.