I've installed 2 Spark 16s to control a 26 valve system.  All the valves are working fine with this setup.  Are there instructions for the best way to configure this?  I have low water pressure and can't run 2 valves at the same time, so some synchronization between the 2 Sparks is needed.  I could manually setup restrictions on each unit, so they can't overlap, but that seems too coarse.  Any ideas about the best way to program this?