Sums it up pretty well. He sounds most comfortable on Dirty Old Town, which I think is pretty good and the best of the bunch, though as you say, not hit single material. 90.

Good Morning Little Schoolgirl. Not surprised he ended up with Jeff Beck. Stewart instead of Relf in the Yardbirds would be an interesting what if. 80
The Day Will Come. Almost, but not quite. 82
Little Miss Understood, the same. 82.

Perhaps Stewart, like Bowie, benefited from a lack of sixties success. By the time they hit the big time, they were better prepared.