How to at least double your cargo?

At least for "stickable resources". Like Dynamite, and the all new Packager. As you may infer now, instead of limiting yourself to what your backpack can afford to hold, you can go beyond that and "stick" them up on any surface, like your vehicle. Even if it's a flying vehicle, like your shuttle.

Dynamites can be made in your backpack, but you'll also find them in different places. Packagers however, you will make them from Graphite. And if you did intend to use all or most of your Graphite to make Packagers, then this is the way to go.

Keep in mind that you can only make as many Packagers as your backpack's energy will allow you to, which is about 3 or 4. If you're not making more than this, and you won't be needing energy for anything else, then you'll be only ok. But if you need to make a larger number of Packagers then you're better off keeping an energy source in your backpack, like a Small Generator. A Small Wind Turbine, and a Small Solar Panel can work too, but you'll be dependent on the day conditions of course.