Initially, I simply changed the tab position on the settings window notebook to west-north (tabs_wn.png). I didn't like that the tabs were right-sticky and looked at changing this in the following two ways:

1) Changing the tab position to the right-side (tabs_en.png), though I believe they are too easy to miss in this place.

2) Setting the tab minimum width after measuring the titles using the tkinter default font (finding the largest of these and then adding an appropriate padding - for tabs_wn_padx.png, this was 10).
   This meant that tabs behaved as east-west sticky, and text was centred. I couldn't find how to change this to left-justified, though it is possible this can be done through a ttk layout.

Are there any other ideas?

If we do change the tab position, I think it would also be helpful to increase the font size to make them more obvious.

On a separate point, would it be better for me to upload future screenshots to an image hosting site and just include the link in the descriptor message?