Panopticlick's numbers are extremely confusing and borderline useless.
On my initial run, I got an overall entropy of 17.63. My two biggest identifiers were screen resolution (1000x595x24 which was approx 1/22000 browsers) and webgl hash (approx 1/3800 browsers). I fixed screen resolution to 1000x600x24 (approx 1/85 browsers) and disabled webgl hashing (approx 1/6 browsers) and the overall entropy did not change one iota, despite also closing browser, flushing cache and cookies, etc. I gave it another run with a deliberately weird resolution (1420x701 which was something like 1/105000 browsers) and once again, the overall entropy was exactly 17.63. So based on my experiment, it seems that screen resolution and webgl hash have no effect whatsoever on [Panopticlick's] overall entropy score.
An update on last night's experiment, if anyone cares. The next largest identifier was system fonts (approx 1/1300 browsers). I set `browser.display.use_document_fonts=0` which hid the system fonts (now the same as approx 1/10 browsers) and my overall entropy dropped to just below 11 bits. At this point, none of the metrics were less common than 1/10 browsers, so I figured I wouldn't be able to do better than that.
As a side note, I ended up re-enabling system fonts because disabling them broke a large percentage of web sites' CSS.
On my initial run, I got an overall entropy of 17.63. My two biggest identifiers were screen resolution (1000x595x24 which was approx 1/22000 browsers) and webgl hash (approx 1/3800 browsers). I fixed screen resolution to 1000x600x24 (approx 1/85 browsers) and disabled webgl hashing (approx 1/6 browsers) and the overall entropy did not change one iota, despite also closing browser, flushing cache and cookies, etc. I gave it another run with a deliberately weird resolution (1420x701 which was something like 1/105000 browsers) and once again, the overall entropy was exactly 17.63. So based on my experiment, it seems that screen resolution and webgl hash have no effect whatsoever on [Panopticlick's] overall entropy score.