Love this song, ran into some challenges looping it, so the day cycle is cobbled together on the raw file since I couldn't get the on-beat precision I wanted in vfxeditor. That brings the song to 15 minutes, it'll then have a slightly janky loop that I couldn't do anything about. I think I made it long enough that it'll be barely a blip, but if you're listening for it at the right time, you might catch it, it's about a tenth of a second earlier than I wanted.
I may just end up extending the song to 35 minutes so that there's no loop to worry about at all, we'll see. Maybe as an optional file.
Note as always with mods that change default BGMs, you will need to put this in your Default/Base collection in Penumbra.