Questions re setting up tags for dynamic remarketing
The category example on this page https://support.google.com/adwords/answer/3103357#custom_parameters
appears to be wrong. It looks like they have just repeated the product page tags.
Also I'm not sure what to do with my multi-step checkout, is it 'basket' till they have paid, then 'purchase' on the confirmation, or 'basket', then 'purchase' for everything after?
Re: Questions re setting up tags for dynamic remarketing
In the right-hand column on the category row, it says "You can also add an advanced custom parameter to send AdWords the category type (example: ecomm_category)." It's just not shown in the sample code.
For your multi-step checkout, I think you're asking about which page type to choose? You'll want to use one of these:
I'm not sure about your checkout configuration, but I'd think you'd probably want to use "cart" until they reach the purchase confirmation page and then give that page the "purchase" value.
Let me know if that doesn't answer your question!