The point at which one has "enough" for a book (of verse) is not a quantitative matter alone: it comes at the end of a paragraph, or chapter, however short; it's a question of form. One only has not enough, when one feels that the poems written require the cooperation of certain poems not yet written, in order to be themselves quite.
The paragraph, or chapter, metaphor suggests that a book of verse should have a completed shape, not necessarily a narrative arc, but whatever is proposed at the beginning of the paragraph or chapter would have been developed to some satisfying (Moore would have said, joyful) conclusion. Demanding as the metaphor may sound, it is also liberating, for a paragraph or a chapter is not the whole book, is not the whole work of a lifetime. There is time and space for later paragraphs and chapters to develop, modify, or even contradict, what has been said.
Moore's reading of Genung's Epic of the Inner Life affected deeply her writing of "In Distrust of Merits," her WWII poem. The book has something significant to say of the book of Job:
...the book of Job is too much like real life to be a didactic teaching with a single self-evident answer to its problem....Why does suffering upon suffering befall the righteous--is unsatisfactorily answered in the apparent fluctuation of its reasoning, the unity of the book being centred in a person--Job.
Not why & how God deals with man, but what Job is, is the vital question...the book is an epic of the inner life--a drama within the individual soul.
And if Job has wrought the answer, then the answer exists in humanity--: Answer: There is a hunger for God and a loyalty to him, which survives loss and chastisement.
But the answer is not put in words. It is lived.