Hi James, I'd argue instead of wasting too much time on templates and optimizing for clicks, you could put the emphasis into the email copy and telling the story of your product launch.
Your leads probably don't care about color schemes or how nice your emails look. They care about how your product can help them do their job.
As it happens we just launched Drift Email for Marketing and we even have a pre-packaged Playbook to help you share your product launch news.
More details: blog.drift.com/drift-email-marketing
happy to chat more about it if you'd like.