Hi
Yea, I know of how to use WebHarvy, to extract likely patterns only. Are you sure whatever you are looking for to scrap, can be scrapped through pattern based scrap? To what I'm experienced with Amazon, there are few details that can be scraped through patterns (for instance, Total Ratings, Ranking etc.), but you cannot scrap all rating details of each ASIN.
Further, there are APIs available to download data from Amazon. Appreciate if you could discuss further about your requirement, and I assure to provide my honest recommendation.
Thanks
Amazon MWS/AWS/Seller Automation expert