Hello Luftmensch
This question is often asked, and there is no single answer - it depends on exactly what is required. In most cases it is best to submit the answers that are to be entered in the grid. In some cases, of which the wonderful Shawshank Redeption-themed puzzle was the best example, the grid itself requires modification, and that approach does not work. PS - I no longer submit solutions, so have not had to worry too much.