Tamsaddle has some good foundation stock, so you could buy with confidence from her. However, I wouldn't jump into breeding until you are aware of all the implications (ongoing care/cost; having two litters per year to keep fertility up/ sourcing a boar). Getting into breeding is a big commitment, and a major tie, if you want to have a bit of a life.
Also, as you are concerned about helping rare breeds, the best ways you can do that are 1) buy meat weaners from a good pedigree breeder, to help that breeder keep breeding 2) breed from pedigree stock yourself - as only birth notified AND subsequently registered offspring can be counted in the official annual breed surveys.