Presently zoom level has a default value and relies on the player to adjust it, should the page be bigger or smaller than what can fit in the default level. a GM should be able to set a default page zoom level. This way if you over or underscale you can be sure that the user gets to the page at the zoom level it was designed for/fits in. Also,as the GM you wouldn't have to change the zoom level dozens of times as you work on the page