I think its worth noting that if your just using a single Hubspot form, you could just grab their markup, strip out all non-essential markup and add markup and styling to what remains manually. Not sure its worth installing a new module especially one that's so tedious to configure.

I see this all the time with sites that give you markup to add their widget to your own site. A lot of times it comes with unnecessary markup that you need to cleanup in order for it to fit your site.