Just reporting the same issue, also on a retina screen, on 14w29b
I did try that, and it changed the size slightly, though not to the expected size. See the new screen shots to see the result.
This is when I set the resolution to 64x48, just as a test.
This is the options screen after I set the resolution in the Profile Editor to 640 x 480
I was thinking it might either be because I run my laptop in "scaled" mode (Retina screens can do this on OSX), or because I had connected it previously to an AirPlay TV, but after much testing, neither seems to be the case.
I'll try locking the resolution in the profile editor and see if that makes a difference.
Edit: Nope, I just tested by locking the resolution in my profile to 640x480 via the Profile Editor, and it had no impact. Actually, It did have a small impact, as now I can see the edge of a button. Still zoomed in to a huge degree, but the edge is partially visible.
That's not a good long-term solution as it really ruins overall performance.