You're right,
@Missie there isn't a right or wrong answer to drafting and tools. Even here, we all use a variety.
As to systems, I use a men's wear book from Italy (I have a copy of the book the old man had in Men of the Cloth documentary, Moda Aloi - Il Taglio del sarto moderno ca. 1933 and use that one to draft men's wear for the most part...I learned the German Muller und Sohn so menswear is centered totally in European methods), learned Helen Armstrong in school and use a cross of Connie Crawford, Furrer, Alderich and Soviet Era methods (weird cross of Euro-American methods) and draping didn't hit home (Armstrong) until I started watching Nick Verreos on You Tube, University of Fashion and got a cross of books from the 40s-70s.
We all find what works best in what we do, even with tools.
@Irishseahorse I have the Fairgate Fashion carry all from Wawak, which I needed for school and I use the half size L square and cuff ruler from it. I use the vary forms in other tools and the french curve I use the smaller one from Lutterloh more then this one. Tools are a lot like systems: we all find what works best for what we are doing.