I have a dynamic operational layer in Maryland State Plane that I am placing over the ESRI basemap (Web Mercator) and it works fine. What I started wondering, though, was whether or not I should reproject in the map service by setting the data frame to Web Mercator instead of MD State Plane and then bring in the feature class and specify the transformation. Does it matter to what happens when the Flex map is composed in terms of the server effort to process the data or to feature registration (no measurements will be involved)?
Thanks,
Marc
