I'm starting a Seal Major 30cc build. My first full engine machining project. Getting ready to order a set of small taps and dies. Is it necessary these day to build with BA or is there a greater selection going metric? I should mention I'm partial to Allen heads. I would not want to swap back and forth if not absolutely necessary. On past projects I have seen advantage in swapping between imperial and metric on occasions where available space has been an issue. Does this ring true also for BA? Thank you. ps. Who has really good quality kits?