Hi Stephen,
In 9.3.2 release, we added a new command (Minimize_Browser_Window) used to change the position of the window by providing X and/or Y position points, which can also slightly resize the window. The command (Maximize_Browser_Window) changes back to maximized.
Now I know that's not the exact requested feature, but we're also working on adding more options to this command which will be used to specify the resolution in pixels. A response will be provided here once this feature is deployed in production so that you can upgrade and be able to use it.
Regards,
Subject7 Team