You cant go wrong with a 1.5l bottle, theres plenty in there for a few hopper loads. i3s are good goggles, i just bought some after a bit of picking and choosing and borrowing and boy are they COMFY! Feels like you're wearing nothing at all, nothing at all, nothing at all....
Im getting an Ion as well, bought off the infamous Fish through my mate, should arrive for use thiss weekend (maybe, perhaps if it gets sent special delivery... )