Relative size for blur in VSE Is there any way to have relative size instead of absolute in Gauss strip?

Final output is 4K, while I am working with 30% preview. It is very annoying to switch between render sizes just for tweaking correct amount of blur.
There is no built in functionality for this. However, you might be able to achieve what you want using drivers. Use the Render resolution as the variable. Perhaps you could define a custom property for the total blur value?