Wouldn't that preclude the need for a check valve though?

 

The check valve maintains a vacuum in the lines when there is a low vacuum condition in the manifold/keg.
The vacuum resistor will extend the period of time that the systems will continue operate under the low vacuum condition... it should also make it slightly more tolerant of minor leaks.

 

Reservoir doesn't help if you don't have functioning check valves. Need to be able to maintain the vacuum, if there isn't a check valve, it will just equalize pressure with the intake.

Sometimes I think a LARGER reservoir would be the hot ticket as well.