I like the shelf in a WB blackbird but a no-sew-um mesh ridgeline bag is the most useful for items you will use most often like headlamp, knife, bug repellent etc. You can make these RL bags yourself or buy them. If your tarp is working well shelf should stay dry but in an extreme rainstorm what I hang along the ridgeline is generally the driest, I.e least mist and morning condensation, but your experience may vary. Waking up to find your coat all wet is not fun. This has probably happened to you in a tent if coat was up against the side or on floor and it rained a lot. Similar problem if rain blows in on side WBBB shelf is on and your coat is there. This is not a design problem with WBBB just something to think about.