First of all, get rid of the "rope" and just take some string.
- next -
The compactor bag as liner should have - inside - anything you don't want to get wet.
(the white trash compactor bag is the best tool I've found for waterproofing a small lightweight backpack. 2.1 oz and it waterproofs EVERYTHING)
You can nix all stuff sacks (pretty much) except for the food bag. No stuff sack for the sleeping bag, and nothing for clothes.
If it's a nice day, so don't worry. But, if it looks like rain, I put it ALL inside except for:
Rain gear, that can stay on top, outside of the bag, because you'll need that if it rains, right?
And, I sometimes (but not always) put the sleeping tarp UNDER the bag, in my pack first. If it's raining and I have to set up camp, that'll get wet regardless.
AND - If it rains at night (or if it's dewey in the AM), I stick the tarp in the bottom, and the plastic bag on top, that way the contents of my COMPACTOR BAG stay dry.
If stuff gets wet, it gets heavy. And if it falls in the river on a nice dry day, I still want it protected.