Welcome to NSI Australia!
The bridge side is a blessing for getting close to the skin, sidewalls and cuticle line.
What Endurance File is recommended for use on the natural nail?
Any 180 grit file is best on the natural nail to avoid overly filing and thinning of the natural nail. If you file with an extremely light touch, the Endurance 150/150 will work as well.
You can use your old files and old buffers to clean and remove the excess of polishes or gel polishes. It really works like an eraser on the excess or colours , when you run the file of buffer and slide it along the nail in a perfect straight line and direction. No fiber = No mess!