We're both talking about the same thing I think. Capacity on the hulls and size of the components. Right? For example: Cargo Hull = 55 capacity. I've done some miniaturization and it's stayed 55. Component sizes for the same hull type (ie Cargo) have not decreased either. I compared, say, sparrow missile size before and after miniaturization for the same hull (Cargo). Bottom line is that I can't put any additional components on a ship after miniaturization research.

Am I missing something? Is there a project I need to build on a particular planet to get the bonus (ie xinathium hull plating from "Advanced Hulls" research)?

Thanks for the help, I appreciate it.

Wow, guess I forgot just how confusing it was after playing a few months.
Kyro's right about actually having to pick a hull type and then the miniaturization shows in the bar at the top of the ship screen.

No modules at all, or were you just picking ones larger than size 12?

Sure sounds like a bug -- maybe it is displaying a space that is larger than you should actually have from the miniaturization that you got. Have you checked how much space you should have with your miniaturization? I'm finding a lot of little bugs popping up all over the place with update 1.3. Sure hope they clear up with 1.31.

Miniaturization was very convoluted in 1.2 and had problems. It works perfect in 1.3. That's one change in 1.3 I really enjoy.

Even the name is convoluted as it expands the hull rather than shrinking the component's size. It had to be this way since reduction in module sizes would be lost in rounding. Calling it Hull Expansion would have made more sense.

... or maybe it can be interpreted as the extra space coming from various internal components and systems that come with every ship by default being minimized so that there is more room for weapons, defence systems, engines, and such?