[Al Skierkiewicz]

Originally Posted by DavidGitz

There are a few threads on this already, but we are thinking about using a servo attached to one (both?) of the flow control valves on a piston. Not ideal I know, but it won't require many parts.

David,
A servo won't give your the range you would need. The flow control valves are needle valves that may require a few turns to get to the desired flow rate.