I would be hesitant to compare a bloodline in Alberta with one in Kansas.....that being said I have found a large percentage of them will buck a little and stay with it for a while. Very impressed with their work ethic, as in lot's of bottom, lot's of try and the odd one with unbeleivable stamina.
They don't seem to work out very well for the "grab out of the pasture every couple of month's for a Sunday afternoon ride with the grandkid's" they need a job to do and the steadier the better. Same as any other bloodline though I'd look at how much Hancock, how far back, what else is on the paper's? Anybody close up that's proven? (to me that could be the neighbor's old stud that never traveled more than 50 mile from home, if I like him : )
Then I'd throw that all aside and judge the horse on it's own merit's, which can be a little hard if your talking broodmare, due to age, injury, lack of trainning.....
I did a colt starting demo for a local club a few year's ago and they had a little grey mare all spit and fire. Hancock and Blue Valentine breeding. It was.......interesting, and probably entertaining to watch
After the demo they raffled the horse off and I thought "great now I'm going to be known forever as - you know that guy that started that colt that maimed 3 people"
As luck would have it she went to a guy that's just a tad tough, you know wear's his boot's out from the inside? They get along great, he told everyone she was better started then any 30 day colt he's had, after 5 session's (3 ride's in a 50 ft pen)
More than you wanted to know
but hey you didn't HAVE to read it all