Simply head to a local work bench where character exchange is possible(e.g. Sullustan workbench in Nar Shadda). Equip Bao Dur and Visas Marr; this should provide you with adequate skill coverage(Sentinal skills and the technical). You must access the workbench with the character with the high skills. Being items are entirely random throughout the game, excluding quest/character related items, this is your only reliable(and best) source of lightsaber upgrades. I was also under the influence that breaking down items while using a character with higher repair skill provides more components. My Sith Lord's Saber is dishing out a good 28-60 with the highest quality components(Personalized crystal, quixioni, pontite lens, expert fenching emitter, and ultimate diatum energy cell).