Thanks RhinoFish for the link.
I've scanned a number of pages but cannot find a definitive answer to my question.
Is it best (for me and my budget) to make a number of product feeds OR do I have a number of product Ads or Groups or Campaigns each using the same product feed but with filters.
I don't trust Google not to show inaccurate adverts, i.e. if I leave it to Google to use the product_type to work out what it's going to show I'm sure it'll work it out that I have a product that always meets it's 'algorhythm' in order to burn through the budget.