Oh my Goodness! I was finally able to get it to work!!! It was a simple but completely non-obvious solution. If you open EpicGM on Mac OS and it is full screen and poor resolution, and it won't respond to regular method of switching between full screen and window mode, try this:
1. Click on Mission Control or swipe up on Trackpad with four fingers
2. move moue pointer up to top where you see desktops, and EpicGM will be shown as it's own desktop.
3. Hover mouse over Epic GM desktop and you will see the minimize screen in top left of small graphic of EpicGM desktop. Click on that and it should be back to Windowed.
Not that I've done this, switching between windowed and full screen works normally, but before this, there was no regular way of swapping between the two modes. Very interesting, but glad I fixed it. So much easier to create content on Mac and then use Dropbox to view it on iPad!
Looking forward to version 2.0