I only called it BONDO , instead of Body Filler because everyone in the industry calls it Bondo or Plastic , never used the Brand Bondo , as I always use PPG's Body filler's .
Just wanted to mention this .

You shouldnt have to cover the whole area if its minor imperfections , if your filling sand scratches and wavey body work , then it wasnt ready for primer . as the polyester puttys can be used over the body filler for filling the imperfections before priming too . ( FYI )

Just dont use the old Lacquer spot putty of years ago , as it will shrink , and you will see everywhere you used it after a few months !

SprayTech