Some helpful
suggestions which you may wish to consider:
Your three choices you give the reader are immediately at the end of a story, with no demarcation of any kind to offset and/or distinguish it from the story immediately above it. You may wish to rethink that strategy.
Also, where there are verse insertions, you may wish to use a different font and/or somehow separate it in some fashion from the body of the text immediately before and after said text.
Too, you may wish to join paragraphs, rather than have a space between each paragraph. I don't believe I've seen any of Lovecraft's stories with spaces between each paragraph - to the best of my knowledge. And one certainly does not find them to any great degree on published books.
You may want to reconsider removing the ragged right margins. Although I'm certain some books have that (and some people
do prefer ragged right margins), I know that most published books have justified right text.
And finally: I personally think your ebook would look more 'professional' if each story started on its own page.
GOOD LUCK WITH YOUR ANTHOLOGY! 