Some other uses for those tools:
Some people use hydrogen to 'shoryuken'-ram enemies. This way, you have not only a high forward velocity, but a high upward one as well. Works best in ships with large balloons, so you ram with the balloon, not the hull.
Chute vent also helps get you lower with carronades, in case an opponent with a popped balloon drops below the vertical firing arc.
Hydrogen can also be used to go above Pyramidions, and since the nose cone limits the vertical firing arc of the front guns, this can put you back in to a more advantageous position. Likewise, it can be used on a Pyramidion to bring your guns back to bear on a high target.
I personally used Vent and Hydro on my Squid for a long time. Normal maneuvering in the vertical plane is pretty slow in Guns of Icarus, which means that unless they have a buffed balloon or the same item as you, using one of those items is effectively an out-of-plane maneuver, which allows you to disengage if you're at a disadvantage. Similarly, it can quickly bring you in-plane from an out-of-plane position, which means you can move from being out of an opponent's gun arc into a close engagement very quickly--useful for carronades and flamethrowers.
As for dealing with the damage, there's a bit of finesse to knowing how much altitude you need to gain or lose. If you keep Chute Vent on until you descend to your desired level, you're probably going to faceplant into the dirt. There's also a bit of premeditation that helps--if you prioritize balloon repairs shortly before when you know you're going to use a balloon item, you can avoid a pop.
