Hi
you want and need all of the written part of the selvage plus minimum 1/4 inch of fabric.
When I am saving my own selvages l give myself 1/2 an inch...
but if asking friends .. I am happy with 1/4 inch which will becomes the seam.
that way I don't loose any of the writing.
if you only get the written part it is very hard to do any thing with that selvage.
your seams become too small.
Hope this info help...