What's best practice for cart pages?

[VM-Oz]

i don't mean e-commerce site in general, but the actual cart page itself.

What's best practice for the links that customers click to add products to the cart, and the cart page itself? Also, I use vanity URLs for my cart links which redirect to the actual cart page with the parameters applied.

• Should I use use 301 or 302 redirects for the links?
• Do I make the cart page's canonical tag point back to the store home page so that I'm not accruing link juice to a page that customers don't actually want to land on from search?

I'm kinda surprised at the dearth of information out there on this, or maybe I'm not looking in the right places?