Currently the system is limited to 100 mile radius due to the density of fishing spots in certain areas. For example, many places in Florida have over 11,000 fishing spots in a 100 mile radius. A 300 mile radius could potentially degrade the service by taxing the servers with a huge load when creating the files. However, as a yearly subscriber we can provide such files as you request. Simply send us an email and we will send you the file.
Alternatively, you can create 100 mile radius files using the Fishing Map. See instructions for the options here: https://fishingstatus.com/places/maps/custom-fishing-spots-maps