Sorted by percentage increase:
SUPERMAN == +119.9%
BATWOMAN == +81.6%
CATWOMAN == +67.3%
WONDER WOMAN == +57.3%
RED HOOD AND THE OUTLAWS == +55.6%
JUSTICE LEAGUE DARK == +50.8%
BATGIRL == +49.9%
HARLEY QUINN == +49.3%
GREEN LANTERN CORPS == +43.2%
AQUAMAN == +39.8%
FLASH == +37.8%
EARTH 2 == +36.9%
ACTION COMICS == +34.9%
DETECTIVE COMICS == +33.9%
BATMAN AND == +33.6%
SUPERMAN WONDER WOMAN == +31.1%
GREEN LANTERN == +28.7%
BATMAN == +21%
JUSTICE LEAGUE UNITED == -2%
Of course, SUPERMAN also had a high-profile new creative team, so it would probably have had a big increase anyway, but probably not quite as high an increase. The only one to drop in sales was JUSTICE LEAGUE UNLIMITED, which was the second issue. In normal circumstances, that #2 would have seen at least a 20% drop, so holding at just a 2% drop is effectively a large increase in the range of the other books.
SUPERMAN == +48.6k copies
HARLEY QUINN == +30.8k copies
BATMAN == +22.6k copies
DETECTIVE COMICS == +18.5k copies
WONDER WOMAN == +17.6k copies
BATGIRL == +15.8k copies
BATWOMAN == +15.1k copies
SUPERMAN WONDER WOMAN == +14.9k copies
ACTION COMICS == +14.3k copies
BATMAN AND == +14.2k copies
CATWOMAN == +13.6k copies
FLASH == +12.9k copies
JUSTICE LEAGUE DARK == +12.9k copies
AQUAMAN == +12.8k copies
EARTH 2 == +12.7k copies
GREEN LANTERN == +12.5k copies
GREEN LANTERN CORPS == +12.3k copies
RED HOOD AND THE OUTLAWS == +11.8k copies
JUSTICE LEAGUE UNITED == -1.3k copies
Taking out the two special case extreme values, it looks like the gimmick was good for about an average of 15k copies, or a 45% increase.
The same open order variant covers continue with the themes for July ("Batman 75"), August ("Selfie") and October ("Monsters"), with September having the 3-D covers for their "Futures End" one-shots, so we'll see how the sales do with those themes. I suspect that they'll all decrease from the June numbers, but stay ahead of the May base numbers for a few months.