Allow specifying preset as percentage

I have a laptop. I connect it to docks at home and at work.  I have different sized displays at each location.

Instead of me having to define presets that make sense for my display at home, and display at work, it would be really nice to define a preset that is relative to whatever I am currently using. So let me set a preset like 90%x90% and have the extension figure out the size of the display and use that.