We develop a Delphi application as a client in a custom 3-tier environment, where the middle tier is a .NET application server.
We are considering to replace our recent solution with TClientDataSet by FireDAC TFDMemTable, because with TClientDataSet we have speed and memory problems.
As far as understand the architecture of FireDAC, if we implement a custom implementation of a FireDAC driver, which, instead of connecting to any SQL engine, connects to our application server, then we can use the complete functionality of FireDAC datasets, incremental fetching, local datastore, etc, right?
Is this kind of customization of FireDAC encouraged? Are there any examples existing? Is there any guideline or documentation for FireDAC driver development?
Is this a difficult task or achievable? What is the rough average estimate for engineer hours to develop a FireDAC driver ? (the back and data access is given)

(snip)

FireDAC driver API is not documented. In any case it is a complex task,
  which is ~ 2 months for develoment and ~2-4 months to make the driver
  really stable.
  Instead you should consider to use a custom mtier client, which will
  deliver data to the client and will populate TFDMemTable. Other option