For most of the required parts the only option is to buy the products they appear in. I.E. if you want to make Odin/Deathscyther Heavy Defence you should buy:
B-12 Deathscyther Oval Accel/B-19 Odin Central Blow for Deathscyther/Odin.
For Heavy and Defence however you can get BB-05 Spriggan Heavy Defence for those parts
You'll probably want to buy Rising Ragnaruk Gravity Revolve when it comes out for the Revolve tip since it's top tier for stamina and at least as good as defence if not better.
B-12 Deathscyther Oval Accel/B-19 Odin Central Blow for Deathscyther/Odin.
For Heavy and Defence however you can get BB-05 Spriggan Heavy Defence for those parts
You'll probably want to buy Rising Ragnaruk Gravity Revolve when it comes out for the Revolve tip since it's top tier for stamina and at least as good as defence if not better.