gtac:
40/30 in the jeans.
I also have a Taurus 85ULBH. It is somewhat larger than the 642, about halfway between K Frame and J Frame. I can't carry it in the jeans, but the 642 disappears into the front pocket. Amazing as weight of the two guns is about the same. Taurus is a bit "blockier" and the 642 is more elegant in design.
As far as "filling" the pocket, it is going to. The right front pocket is 642 dedicated, I don't plan to carry anything else in there. I usually do wear an out of the pants Wrangler shirt when I wear jeans. In the winter I wear an oversized sweat shirt or bulky sweater over my jeans. Pocket is pretty much hidden by outer garment.