I added bar ends to my riser bars (a fashion no-no) ... and they add one or two or more positions depending on the bar ends you choose. I also highly recommend trimming your original bars so you get closer to shoulder width. A 3cm hack off each end made my ride MUCH more comfy. I'm a woman so I may have narrower shoulders.
Bar ends are very easy to put on. You just need to loosen up your other stuff, slide it toward mid-bar leaving just enough room to bolt the ends on the ends. You can also cut old grips to fit them or wrap them with bar tape.