Does page size and relative content position affect SEO?

[FondriestEnv]

Good morning,

Each product page of our e-commerce site consists of a fairly lengthy header and footer. The former of which contains links to ~60 product categories, the logo, etc, while the latter contains information such as the latest posts from our blog, links to support, etc. The main "content" of the page is of course product related information, which also happens to contain a bit of templated data such as links which when clicked open respective sliders containing information regarding our return and shipping policies.

The question: We wonder whether the relative "size" of the page has anything to do with SEO results. As an example, suppose the page header consists of 20% of the total page size, the important page-specific content consumes 60%, and the footer consumes the final 20%. Is this relevant?

Or to rephrase the question: Should we be concerned about keeping our headers and footers as small as possible?

Thanks!

[AlanMosley]

Certainly your content should be substantial, or you will be done for thin content, but what they limit is no one knows for sure, you would also want to see some content above the fold. Google recently bought out a update that penalizes pages with no content above the fold. How I read it, it is mainly for pages that have lots of adds and other stuff and the content you searched for below the fold, but could mean that you need some text above the fold that mentions the search terms.
So if you want to rank for widgets, you would want to have the keyword widgests above the fold.

http://googlewebmastercentral.blogspot.com.au/2012/01/page-layout-algorithm-improvement.html

[Igor-Avidon]

My sample size is small (I am currently maintaining just four sites) but all of them include a large banner on top, which leaves 95% of text content below the fold. None of them have been penalized for this so far, and all of them rank well.

As for the original question, such ratio does not seem to affect standings of the sites I've worked on. However, keep in mind that such heavily skewed page interface tends to look bad, affecting your customers' UX. I would try to keep your footer at most as large as the body of your smallest page.