If you're right handed, is your right or left hand and foot supposed to be bigger?

The first shoe you try on should be for your larger foot. For most people, their larger foot is the opposite from the hand they write with. For example, if you're right handed, your left foot might be bigger. Always fit the pair of shoes to this foot. Even though there are about 20 separate parts to an average shoe, the fact remains that they are mass-produced. It's up to you to customize the fit-- a small heel pad, for instance, works wonders.

https://www.footcaremd.org/resources/how-to-help/10-points-of-proper-shoe-fit

Despite the second reply I added below this shoe professional agrees with this point. (satguru)

This site disagrees, saying the more developed side is usually slightly larger for all physical features. http://scienceinspiration.blogspot.co.uk/2012/11/one-of-our-feet-bigger-than-other.html