Can someone help me here I'm so confused! I'm learning nail technology, wev been taught a gel overlay with tips where you literally apply the overlay and it's done. But when I've watched other YouTube videos lots of them file the top of their overlay like you would a set of acrylics (not so vigorous though). I'm using NSI secrets, and in their tutorial videos they don't file the top. Is it personal preference whether you file, does it just depend on your brand or is it a difference between using hard gel and soft gel?