This looks interesting. I hadn't heard of CaptainDuckDuck. Have you tried Dokku or Flynn(flynn.io)? I had looked at them and settled for Flynn because it had better support for multiple-host clusters.
I ended up just running a single Digital Ocean droplet with Traefik as a loadbalancer/entry point, and then running each of my projects with docker-compose. (And building each project with Docker)
With Traefik I can set up reverse proxying for each project just by adding a few labels to its docker containers, and Traefik manages LetsEncrypt for me.
Dokku has no support for clustering, but it's amazingly simple to set up and start deploying apps. (Digital Ocean has a pre-built and up-to-date image ready to go.) I like it for the heroku-style buildpack deployment, although it also has dockerfile-based deployment. Great little system for low-risk projects.