Around 1-2 minutes. As for looping, I'd say no. While it will loop in the game, I'd think it'd better to have it have a point where it begins and ends. Much like a melody.
Viewing post in Sky Haven: Short Stories (DevLog)
Ok I listened to those songs, and I tried to come up with something that could work as a Title Screen:
https://www.dropbox.com/s/uabyy2oqiizgx7o/Title%20Screen.mp3?dl=0
Let me know what you think.