Should each physical store have its own ecommerce store on subfolders, or share a single national one?

[BruceMcG]

Each store has its own subfolder (in my mind this hasn't actually happened yet ) on the main head office domain i.e. maindomain.com/localstore1 , maindomain.com/localstore2 etc.

I am happy that this is the best structure for SEO purposes. I like the local SEO advantages to it as each store can have its own NAP and show its own inventory. However I am worried that each store having its own ecommerce site will lead to duplicate content issues.

So I am having a rabid debate with myself as to whether each store should:
a) have its own ecommerce website i.e. maindomain.com/localstore1/ecommercestore
b) have its own ecommerce website i.e. maindomain.com/localstore1/ecommercestore with each product and category page having canonical links to the corresponding page on the main ecommerce website i.e. maindomain.com/ecommercestore 
c) just have one ecommerce website with local stock shown e.g. maindomain.com/ecommercestore/productpage shows in an inventory in a line (below the price or such like): " localstore1 (3 items) localstore2 (0 items)"
d) just chill, inventory stock-outs happen just don't worry about showing local stock

And its not good to have internal rabid debates, so I'd like to ask the wider moz community. For bricks and mortar stores (branches or franchises) how would you set up ecommerce stores? Thanks.

[BruceMcG]

I'm thinking c). That way I also get more traffic to the page which helps with CRO, remarketing etc. I don't have to worry about cannonical links and admin of many pages. Also having one SEO page for a product probably outweighs the NAP local SEO advantages.

Any thoughts?

[GregB123]

I too think that C is best, but instead of listing the inventory in ALL the stores perhaps you can have them select their local store and then just show the inventory level at that ONE store for the rest of their visit to your store (or until they select a new local store)

Showing the inventory at all stores may be a bit distracting on the page (bad for CRO) and may lead to lots of customer phone calls asking if you can have something from store A sent over to store B for them (which could be a pain in the butt)

[BruceMcG]

Thanks Gregory, its a tricky question.