[Kevin Sevcik]

It will work. They will not extend at the same time, most likely. Water, air, and electricity all take the path of least resistance, so the piston with the least load/friction will extend faster and/or before the second piston. This would be a problem even with seperate solenoids, though not quite as big. The only sure fire solution is basically to seperate the two solenoids with check vales and things so they're operating from different pressure sources.