Is 256 GB enough for installing Finale on a refurbished Mac mini?

I am considering getting a refurbished 2023 Mac Mini to run Finale, a music notation app I have used for many years. It was recently discontinued by its owner, Make Music. I might also decide to store all my Finale files (478 GB) on this Mac Mini.

I currently have all these files backed up on a Seagate 1TB external hard drive. I am not very tech-savvy and was wondering if purchasing a Mini with only 256 GB of storage would be OK - just to install the Finale app, not the files. Or would it be better to get a 1 TB Mini to hold both the app and all my files? 

I will need to have the Sonoma operating system on the New Mac Mini, and I plan never to upgrade the OS so that Finale will continue to run on it. I don't even plan to boot up the Mini unless I need access to my Finale files sometime in the future. However, I would like them to be available to me for as long as possible. Twenty years would be fantastic.

I would be very grateful for any thoughts or suggestions you may have. Many thanks!

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