I am struggling to get past the handshake part of the quickstart:
Yes, you are correct. From the log file, your account doesn't have a permission to use Side by Side Integration API. You can use Eikon Data API (APIPROXY).
If your account has a permission to use Side by Side Integration API, you should see SIDEBYSIDE in the log.
[2018-05-18 09:02:57.611|prod] (app) PO: APIPROXY, SIDEBYSIDE
You can contact your TR account team to verify the account's type of your Eikon login.