Hi,
I teach a course on Udemy on this ([login to view URL]), and I have extensive experience preparing manuscripts for publication on Createspace. I have also worked for a small new York publisher on interior book formatting for a year.
I will work with you to decide on the best trim size to achieve optimum page count, and then format the book with attention to typographic details. Unlike most book formatters, who opt for one or the other and leave it at that, I will ensure your book has no widow/orphans, and also has even feet (so you don't have stray stub lines at the top or bottom of pages, and the text block on either page is balanced perfectly.)
I will also proofread as I complete each page, correcting any obvious typos or spelling/punctuation errors that may have slipped through editing. However, unless I find anything major wrong, I won't comment on style, or check facts, as these are jobs that should already be done before you move into formatting the book.
I can complete the manuscript in Word (so that you can make any small edits later) or in InDesign (which enables finer control over the layout, including outdenting punctuation) and save a print-ready PDF ready for upload to Createspace for you.
If you have any questions, please inbox me for further clarification. Current turnaround is 3-4 days for a book of that size.
Gail