Google business and SEO for a product not necessarily multiple business locations

[FPK]

I'm SEOing for a company that sells back relief medicine on a national level. I have several questions since I'm not sure how to handle SEO for a product compared to a business.

How do I handle google business listings? Some of the stores selling my client's product may or may not have business listings created. Do I try to aggregate and setup for all locations and then create separate contact pages on the website? When I check other companies Ex. www.backrelief.ca they don't have a Google Business listing it seems.

Would a Google+ Product page and a link to the website suffice?

I noticed on some websites they'll have a "where to buy" page which tends to link to a store page or a page listing store locations that sell their product. Would this be the best option to handle the situation?

[GlobeRunner]

If it's a national business appealing to a national audience, then I would consider NOT setting up Google My Business listings. I have seen a national business set up their local business listing (Google My Business) and they ended up losing a ton of traffic overnight. Their mobile traffic, which was coming from various cities in the US, was good. When they set up a Google My Business listing, Google started only sending mobile traffic from 500 miles within the business location.

If you're a national business, then you shouldn't necessarily set up a local presence.