Im a sea leveler and I've been training with an osprey talon 2 pack with a hydro bladder. I was originally planning on running with(it'll hold a light weigh jacket, some gels, my phone for some cool pics, and h20 of course). I'm planning on just filling the water maybe 1/3 to save weight but wondering if its gonna be more harm than good even using it. If appreciate any advise. Oh my goal time is between 4:30 to whenever I get to the top.