Having a lot of trouble with GUI scaling

I’m working on an old-style RPG for practice with Unity2D. Right now I am trying to simulate a dialogue box like you would see in any RPG.

My issue is that it seems no matter what settings I use, I cannot get the size of dialogue boxes and text to be consistent. Ideally, regardless of resolution I want the boxes to always occupy the same amount of space, and the font to always be the same size and laid out the same way.

I’ve tried playing with the Canvas Scaler options, adding Horizontal Layout Groups, Content Size Fitters and my lack of experience is just stomping me.

As an example, if you look at the newer game Cosmic Star Heroine, it handles the dialogue boxes and texts the way pretty much how I would want to. Even scaling the resolution up quite high, I can still make out how many pixels are in the font.

I’d like to get this working in the GUI before I even look at scripts, so I have a good idea of what settings I am playing with. If anyone could point me in the right direction, that would be amazing.

EDIT - For clarification of what I’m trying to do.

I made a basic canvas with a panel and a text component:
Canvas - http://imgur.com/JSmg2d9
Panel - http://imgur.com/p0b1Ijq
Text - http://imgur.com/ldAR5Fa

If I keep the aspect ratio at resolutions of 16:9, it works great and always looks the same. (At least close enough). Howeverm if I switch to a different aspect ratio, the text will jump around and words with move to different lines, etc.

16:9 - http://imgur.com/maeHeb5
4:3 - http://imgur.com/NjdqXOx

The text clearly is shifting around on different aspect ratios.