I had a little time today, so I took my first baby steps.
DriveThruRPG is ceasing support for Scribus. They recommend Affinity Publisher or Adobe Indesign. I don't love the subscription model that Adobe works under these days, so I purchased the more affordable option - Affinity.
I know literally nothing about how layout software works. In the next few days I won't have time to learn anything, but I feel like a little progress has been made.
I have a plaintext version of Mini Six, which I'll be revising extensively. I have some ideas of what will or may be added, but I won't commit to anything in particular quite yet.
I know that I'm putting the cart before the horse a bit by worrying about the layout before I have a full text, but it's my personal bugbear. I won't be doing any real layout work until my text is done, but I want to feel confident that I can handle the basics.