I used Valvoline Dex/Merc and Maxlife Dex/Merc in my 98 Camry. It had a slow leak when I got it, and fresh fluid seemed to speed it up somewhat. The Maxlife didn't make a noticeable difference, but a bottle of Lucas PS stop-Leak did. The old fluid was very dark, with globules of a whitish substance floating in it, so I suspect there was some stop-leak in there.
That said, any Dex-III compatible fluid should work fine, and Dex-VI is an upgrade. The turkey baster method will get fresh fluid into the entire system, since it's moving through the rack and pinion every time you move the steering wheel. I don't know what percentage of fluid sits in the hoses and rack, but a fresh reservoir, followed by a drive, and another fresh reservoir should replace most of the old fluid. Then do drain and fills at whatever interval you're comfortable with, and the system should stay happy.