This sounds like a tricky situation to be in. If the product info on the site is static storing it in a db with DataAssist would just allow you to have your own personal copy of the info. Unless you can get the product details to come from this db it will not change the nature of the sites and the products on them and updates will still be done manually to static items.
Your idea about creating a cron job to run the script regularly would definitely help to ensure that your copy of the info in your db is up to date.