to cite a different answer on a similar question
SEO questions should be asked on Webmasters, tagged with seo.
Reason: the whole area of SEO is as big as Magento as a whole. With a difference, that there is only a very small overlap of SEO with Magento Developers.
Doing SEO in a professional manner requires access to a few hundred websites at the lowest, the right connections to other expert People in the Field (like we Magento people are good connected to other Magento people) and reading a lot of news and books and so on.
If you want the best possible SEO answer, you should go where the experts are. They will not be here in the Magento Stackexchange