nvm
Found the answer a bit lower down in the SSO Tutorial:
If you take a look at the example SSO extension above, you will see a VENDOR_CONFIGS dictionary. SSO extensions are located in the Q2_Vendor database table, whereas other SDK extensions are located in the Q2_Form table. This means that SSO extensions can not use the standard Wedge address configs. If you need values stored in the database, use VENDOR_CONFIGS. For most development purposes, vendor configs work exactly the same as Wedge address configs. Define them in the extension, and they are populated into the database at install and can be changed. Access them in your code using self.vendor_configs.get()