That’s an average of 86.7 yards detangled per hour.
To get an estimate of the total yardage, I took one ball of yarn and re-wound it into a skein (2-yard loop). I got 188 yards. Then I weighed that skein. It weighed .65 ounces. That averages to be 289 yards per ounce. Then I weighed the total amount of yarn that I’d detangled (4.50 oz) and multiplied by the average yards per ounce. Thus, approximately 1300 yards.
I now feel that I have a better understanding of how this lace-weight yarn behaves. I’m hoping that will make knitting it that much easier and all the more interesting.