I've looked at : http://www.patentsview.org/download/ and the "claim" download is 10GB in size. Is there a smaller download size location can download patents over past approx 30 years in xml/csv format ?
You can download bulk patent data from USPTO: Bulk Data Storage System. Look for Patent Grant Full Text Data.
Google used to collect patent data and provide bulk download, but they discontinued the bulk download project because USPTO provides the bulk data now directly. But you can still download bulk packages of what Google has collected prior to discontinuation.
The bulk patent data sets are available at USPTO to download for free. You can follow this link - USPTO: Bulk Data Storage System
I believe that at Patentsview.org, they offer patent gazettes which contain extra information about every patent filed in a respective period of time like, drawings and claims.
At USPTO: Bulk Data Storage System they have the gazettes as well as full patents data sets in various formats. You can search for "Grant Full Text Data" to download them in a smaller version.
XML downloads don't have images, hence are much smaller in size and easy to download. You can even download the Bibliographic Data to reduce the download size to minimum.
You can make direct API calls to the PatentsView.org api endpoint to filter down to only the data that you need. The problem I see that a vast majority of the 10gb file is actually produced in the last 30 years or so. The data set might not be smaller.
For what it's worth, I am the Head of Product at IP Street. We provide enterprise grade patent data APIs and analytical algorithms like semantic patent search. Sometimes it's better to have a vendor like us do the number crunching for you rather than download and manage the 10gb of data yourself.
I am interested in learning more about your project. Reach out to me if you still need help.