Thank you for the feedback!

1 - I experimented with some calibration involving staring at a point, but I found it troublesome as blinking would make lead to some inaccurate calibration data (webgazer doesn't have blink detection). It was also a little more fatiguing since the user would have to really focus on staring the entire time. I found that it was less mentally fatiguing if the user could control their own calibration give themselves room to blink or just rest their eyes for a second.

2 - Ghost overlays is a really good idea. I'll see what I can do to implement that feature.

I really appreciate you taking your time to write this!