Thanks to our friends at Hitachi a contribution to add a layout editor to the Dashboard has now been merged into master on github - as 2.16.0-beta. Currently this adds a new layout button to each tab layer in the Dashboard sidebar
Clicking it will open the new layout editor that will let you move things around within it more easily (I hope).
If items are "unlocked" - icon top right of each widget - then they are in Auto size mode as normal - if you lock them then the bottom right grab arrow lets you resize and fix them. Widgets can also be moved to other groups - and spaced out.
Note: this is only the start to try to work out what is right - so (encouraging) feedback is welcome
To install from master - it is a manual job -
cd ~/.node-red && npm i node-red/node-red-dashboard - and then don't forget to restart and flush you browser cache.