I think the 340 is the better choice for pocket carry. Similar footprints, but a significant weight difference between the two in a pocket. The Sig would be too heavy in that role for me. It may not be for you. Plus it would be more difficult to draw. The p365 would make a nice compact belt gun providing it's proven reliable and I would test it very thoroughly before carrying since I continue to see problems with it surfacing on the Sig forums.