Hi,
Regarding your job, I want to inform you that I have the required qualifications and skills to bring great success to this position, as you will see in my profile. Over the course of the last 7 years, I have been building a career as a mapping & GIS Specialist, and have many experiences and skills won to offer your open Work.
GIS & webmapping : Design and create web portals, interfaces, and content, Utilize ArcGIS Server and open source web mapping portal environments and databases, Create a custom widget for ARCGIS/QGIS web app builder
Google Map expertises: Polylines and polygons, KML overlays, Ground overlays, We have a lots of experiences with google Maps API geocoding/ reverse geocoding services, Geolocation services, Fusion table: Import data and style it on a map, merge tables of data, Geocoding, Filtering data, Heat map, TablesLayer Wizard, embed map in website.
Note: Since the final output will be KML and you want to make some change in Attribute the Best solution in this case is to Use GIS since you will be to apply Some value using Query. Also 40mb in excel I think That will crash in this situation.
I can assure that my solution will be the Best ( Time & Quality).