Ideally should a 301 or 302 redirect be used from https://www.site.com to http://www.site.com? Is there a valid reason to use a 302 in this situation or would using a 301 have any negative impact on seo?

[k_caldwell]

301 versus 302 redirect from https to http

[Unity]

302 is temporary and 301 is permanent

Personally I'd only use https on pages that actually needed it, like a payment page but I'd recommend you go with a 301 redirect for each respective page.

And don't forget to redirect your non-www URLs to your WWW URLs as well.