WV MK1 Pro

I just got a new MK1 Pro. There are a couple of things I still have to figure out, maybe someone can advise:

* Backpack: all of my backpacks are either too small or don´t fit into the storage compartment or maybe fit but so tightly that there is no space for even a glider concertina bag left. Does anybody have a light but robust and compact backpack that works well for this harness?
* Water: I normally fly with a water bladder, and in summer often fly with 2l of water. Has anybody figured out a good way to route a bladder tube or what other solutions apart from small bottles in the side pockets do people use?