Finally, we made our own pour point (green dot) and made a watershed around just that point and compared it to the other watershed we created. We did stream and watershed delineation and processed our DEM so that the flow rasters we created later would not have sinks that would impede water flow.
I had a little trouble getting my pour point to make a reliable watershed, so I had to make a new feature class again. The new watershed for this point is shown in green with a blue dot for the actual point. I used both raster calculator and batch calculate statistics to get total areas for the two watersheds shown, from there you can just subtract one or the other to see the difference. The rest of the project went great and you can easily see what water would do on this Island with the data created from the GIS tools.