Since about 108 provoke i've been getting less than 0.1 per hour and that's provoking a cu sidhe onto a greater dragon, I calculated I have around a 40% success chance and that seems about right and I succeed about half the time. Since hitting 110 provoke i'm lucky to even get 0.1 in a whole hour of provoking.
According to a post by poo it took him 60 hours to get from 100 to 120, well I've already spent 20 hours going from 100 to 110, so if I don't get another 10 skill in 40 hours then i'm doing something wrong, at the rate i'm gaining skill it's going to take another 100+ hours to get from 110 to 120.
I'm using a non exceptional instrument provoking a cu sidhe onto a greater dragon, the barding difficulty of each creature is 100 and 128.