well you only ever have the choice of a single or double bladed to make, you will have to clear your first planet and then save befroe you receive the saber and use trial and error to get the one you want then you'll need the crystal, if i was you i would do dantooine first as it has a non respawnable (as in her products are one of a kind)(also DO NOT finish the dead salvagers quest as she will dissappear forever and will not return) jedi merchant, this way you can get some power crystals, colour crystals, and other items. but you cant sell her anything just buy... hope that helps