I suggest moving this question to the Products (discussions) section as it will have much greater visibility from other community members. "Community Help and Feedback" is community-focused, not Marketo product focused.
Thanks Dan! It has been moved. Would love any feedback... thanks all!
Permission set should work, but I really do not recommend it as the non authorized users will still see the MSI block in the middle of their page with a superb error message in it...
Furthermore, as this is not documented, I am afraid it is not supported and in case you have an issue, Support will not be of much help.