I'm still thinking about this negative gravity concept. I also scuba dive, the gear is often measured by positive or negative buoyancy, basically stuff that float versus sinks.
I also remembered an episode of Mythbusters where they tested how many HELIUM balloons it would take to lift a person's body weight. the amount/weight of the container (rubber balloons) offset the lift benefits of helium, but what if we did it with existing gear, See where I'm going with this?
I'm not expecting to helium fly, but how about a concept of helium filled gear that would create a slight hint of negative weight. Think about all the gear that has air cavities.
hiking poles shaft. fill it with helium (airtight), is it a hint lighter ?
how about if you took a backpack that's 75L max capacity, used 30L for gear, and leveraged the remaining 45L with helium, would that make a difference?
Multi-use gear, those helium airbags can be re-purposed as sleep padding and pillows.
I suppose there are other lighter than air gasses, by they could be flammable.