Nope – I never got an answer. My data is still not coming across cleanly. When I emailed the developer Zack Katz directly, he shot me back some pricing for services.
As for Marketo, I don’t recall needing to set up anything on the Marketo side. I already had SOAP API enabled, and I just needed to grab the API credentials from the Admin section, and pop them into Gravityforms, and then everything mapped automatically…….except of course for the custom fields….