I am slightly familiar with the sire's side. The dam of my foundation bitch is also Tapscott's Isadorable.
I don't know enough about the either bitch's side to comment, and to be honest, I don't know that you'll get any comments posted publicly anyway.
It may be a bit different in dogs, but I'd highly recommend that you not look at the wins so much as you look at the individual traits that each parent has had to offer. Look up Buddy & Issie and see if you can find out what their outstanding qualities are and what their faults are. They both came from the same kennel (not born in the same kennel, but the same breeder owned them), so see if you can get some information from the breeder, who knows her dogs very well. (She's busy, but she may be of good guidance for you.) Every dog has faults, so you just want to ensure you're not going to double up on something that is critical to breed away from. Likewise, check both parents of each bitch.
Conformation, temperament and health are all very important. Wins are nice and will often give credit to a dog with good conformation, but by one of your remarks, it sounds like you understand how campaigning a dog can really bring their name to the forefront. (I'm talking in general - not about any of these specific dogs listed.)
With dogs, you'll probably want to check the health pedigrees more than the wins. Go to OFFA.org with the registered names and see what you can find in the parents, grandparents, and siblings especially. If you find something you don't understand, ask questions. Hey, if you find a hole in the health testing, you can ask too.
By the way, some of the long-time breeders will occasionally talk about female tail lines, but I think most of the current thinking is that it doesn't seem to prove much in dogs. In fact, I think the only time I hear it mentioned in dogs is when the breeder has come from horses.