Oh, I think I finally got what you mean. :) In every template, you can set Page Width in each Style. So in your, it appears that in two templates you have a smaller max-width setting. Also in each Style Set, you can appoint margins for blocks, so if you want consistent sizing, just set the same sizes for all templates. 

As for making it possible to change column width - in Dolphin, it was very rigid because it controlled the page sizing regardless of template. The layout structure can be controlled by the builder but actual sizings should be controlled by Template Styles, so that you can have a really different look with different templates. We will also gradually add settings like proportional sizing controls for columns in Style sets. 

For now... see in the attached gif how I have set all una.io templates widths to 100%...