Is it possible to add more options in "size of text & images"?

I like this new feature very much but I think it's needing more options. I tried to play with %75 zoom out in my 1366x768 laptop, it's nice to see every detail on a small screen but everything is too small and there are plenty of blank area, that can be filled with a bit more zoom, on %75 option. So is it possible to add %80,85,90 zoom options? If there is any file needs to be edited for this I'm willing to try but don't know which file has these options.