Zollie08, what are you talking about? :S
septeven, there are methods to set/get the instance size here:
http://www.scirra.com/manual/21/the-edit-time
Are you sure you need so much stuff to be accessed from the edittime? We are really pressed for time and I can't imagine why a plugin would need to change things like the WebGL setting? Also, since the edittime side of plugins is a bit limited right now, have you considered just doing everything on startup at runtime in your plugin? Changing any part of the edittime in a plugin is actually really complicated because it has to fully support the undo system, which can be pretty complicated if your plugin wants to make batch changes. I think I need to better understand what you're trying to do to justify it. Are you sure there are no good workarounds?