Some of those racing lines, like, Jet Deck, Croton Oil, Truly Truckle, Tiny Charger and such have many nice, tractable horses.
I would consider the Top Deck a little more squirrely and the Top Moon and Go Man Go were known for some harder to handle horses and some of the Go Man Go were buckers.
Depth Charge offspring would go more by the mare lines, the Double Bid ones bucked well, others took after the dam’s side.
Many Rocket Bars took more after the TB nice, sweet but birdbrained type and rather harmless, as they were more “light” horses than many quarter horse lines, that tended to be, to type, heavier in frame and muscling.
Boston Macs were known for very bad front legs and skin and allergy troubles and a very nervous and hyper disposition and those came strong thru many generations down the line, where today some top barrel racing horses with that line are still very nervous and touchy, although above average athletes, if you can keep them sound.
Two Eyed Jacks and Skipper W are a little more heavyset type, easy going to handle, as long as all goes their way and a little more resistent if they don’t agree with what you want, which makes them harder to train than the much easier, already well motivated, with the great work ethic of the, say, Doc Bars.
A plus of getting the horse bred for what you want is that, for that task, their bred into talent makes them half trained for you even before you start.
Again, we have to warn those that look at bloodlines for characteristics in the individuals that yes, those show thru down the line very regularly, that is why we bred for the known traits we want to the same, but that in the mix, each horse is it’s own individual and may trump all expectations, the good and bad ones alike.