The right length? One famous Nashville writer whose name escapes me once said: Only a fool takes longer than 3 minutes to tell a story. No malevolent intent here, Eddie I think it flows nicely.

Don, I think the length is somewhere between "Hey I want to hear that again" and "Phew . . . it's over."
Ralph Murphy would say: whatever holds the listener between the Coke commercial and the McDonald's commercial in drive-time radio.
In other words - there's no set answer. Google Ralph Murphy and read his columns that you find - interesting reading . . . if you're creating for Nashville. Also Shortcuts to Hit Songwriting by Robin Fredericks.

Happy and Successful New Year, folks.

Ian

Ian
My "Original Tunes" Site
My gene pool needs more chlorine.