Take a look at the Rehr-Morrison nitrous setups, they are using one large regulator for 4 kits...just a different approach. They adjust with jetting, then adjust the fuel with the single regulator. The traditional or most common path is using one regulator per kit. Matter of preference.
the way i understand the rm/speedtech approach is that they run the big aeromotive single return style regulator on the back side of the log or rail.. they also run bleeds in front of each solenoid returning to the cell to keep fuel moving..more of a dynamic approach like fuel injection.. you need a large magnafuel, aeromotive or product engineering pump to supply enough volume so you do not see lean spikes as the systems are activated.. does anyone have any pics of these systems?