Massive Dark Tower fan here... this could go really well, or horribly wrong. Please don't make a metal album and just strap on some Dark Tower artwork; coz that would royally blow. Atmosphere is key with the Dark Tower books, and the same could be said for any music inspired by it. More effects-driven than virtuosic guitar work, imho.
I absolutely agree, dude. This will be a longtime project over years..I don´t make it too simple for me. I´m very open minded to all genres and artistic freedom is the keyword for this project.
Atmospheric stuff will be needed of course!
And at least in Finland (probably the rest of the world too), you cannot copyright a chord progress.