Actually, if you want to solve the Sand people problem on the light side, you can do it and still get extra XP and more importantly, keep the Dragon Krayt Pearl.
Make sure you have HK with you before approaching the Sand people's enclave the 1st time. Try to convince the chief to end the attacks and he will send you on a series of quests which will end with you getting the light side point and some good XP. After settling the conflict, ask about meeting the Historian and they will send you on a quest for the Krayt Dragon Pearl. The pearl is a great crystal for a lightsaber (+3 hit, +2 dmg). Get the pearl, go back and you get more XP and meet the historian, but lose the pearl. The historian is worthless. But then, insult the historian or open one of the wicker baskets and the Sand People attack you and you can wipe out the enclave. There is no Dark Side points because they attack you and you have already solved the dispute. Kill all the Sand People, get the pearl back and some great XP's. Taking out the enclave takes some serious fighting, so plan well before you launch the attack and start away from the chieftain and pick off as many as you can before getting him and his warriors. This will get you the most XP's you can on Tattoine.