A detail gun works well for skis (or a jamb gun).
I also have 3 guns. A fairly inexpensive primer gun and two SATA's; one for base and one for clear. I also have a Binks CUB SLG detail/jamb gun that works well. So, I actually have 4 guns.....
Biggest thing would be to get a gun to match your compressor (other way around is actually better...), although with painting a ski (pretty small) you would be hard pressed to over run even a pretty small compressor.