Can I use REVTeX 4.1 to estimate the length of my submission?
Although using the reprint option in REVTeX 4.1 typesets the text area and font sizes appropriately for each journal, the formatting in REVTeX 4.1 is not exact enough for determining the final length of an article once it goes through journal production (which involves converting the article to XML). Different fonts and figure scalings are the largest sources of error. Use of Times-Roman fonts can partially mitigate the problem. Length estimates at APS are done automatically via an empirical formula. Papers near the length requirement thresholds are sometimes checked manually, but even this process is not perfect. The forms used by the Physical Review journals for manual checks can be accessed from (the bottom of) the Manuscript Preparation document. For AIP length requirements, please consult their web site.