On the larger packbag there are two clips. Compression holds it at the bottom. On the day Talon, it's a single clip and sort of hard to access it in the bottom. Maybe we will here from more hydration users. I'm more of a water bottle guy or sawyer squeeze (which I carry in there often, and personally have not had an issue).
BHA would be excellent , they did have one of our tents at the Denver show. We will be at the Denver BHA gathering in March. I do know there are a couple packs floating around Denver, maybe I can get you in touch. We also offer an excellent return policy and have had very few fit issues. Fit is pretty easy, adjust the harness and hip belt connection you like. As long as you have a pretty normal back profile they work well. You can customize back profile a little, but not a lot. Honestly the biggest issue I have seen from users is they do not realize how close the load rides and how stable it is without much work. Some are used to packs that carry the load back, or belts that slip a bit and feel a need to really tighten it down. With the Paradox, you really don't need to over tighten it much. The belt stays put pretty well, tighten it until it is secure and go.
Yes SHOT was big. To bad we could not get together.