Aluminum welding with the Lincoln SP125 Plus

I have been able to get good welds with the SP125 Plus machine running .030 4043 wire. I was running beads on some 1/8 5052 plate for practice. The difference between a good weld and a bad one is a tiny difference in the voltage setting. It's easy to get too much penetration. I've been running electrode positive like the book said. I seem to remember reading that when welding thin steel sheet metal running .023 wire, electrode NEGATIVE, can be used to help prevent burn through. Can aluminum wire also be run this way in order to weld thin (.062) material? Thanks, Eric