I'm also at the same point you are except I'm using Corso. Before I could make progress on Tatooine I had to upgrade all of his gear and boost his Endurance. This helped with his survivability.
Next I switched my tactics. If you come up to a group of three normals tranquilize one of them, back blast a second one apply DoT to the second and the third. Take them down one by one. With a pair of mobs (one strong one normal) I tranquil/slice the strong, kill the normal and then take down the strong. While the strong is still tranq'd you have some time to heal up your companion/yourself before you turn your attention to them.
Four normal mobs in a group requires the same tactics and possibly Flash Grenading the other two mobs to give you a little bit of time before they start attacking.
It's almost a necessity to use all the stuns that you've got in your arsenal.