I've read that if you were to send off a manuscript it's 250 words/ per page. So whilst writing in a mac pages document, should I section break at 250 words and start a new formatted A4 page, 1 inch margins each way in preparation for eventual manuscript send off. Should I write to the estimated 500 word count per printed page and section break? Or should I just write to fill the A4 page document and let potential publisher format it in future? How do I go about this?