In reply to Reader_Rambles:
I use 3 different dry bags for overnight tramping(NZ hiking), For gear organisation and a bit of redundancy.
I had 1 trip with a miserable night due to a wet sleeping bag, after water kept getting into my pack when opening and closing it, gathered at the bottom of the pack and the light weight dry bag wasn’t up to keeping it out.
So I now use one heavier weight kayak type dry bag (Sea to Summit dry river), that has my sleeping bag, mat and down jacket, that sits at the bottom of my sack.