So I did a longer ride this morning and as I suspected, these tires are too big and too heavy. It felt like a truck! So I swapped them out for the Specialized Hemispheres I had mounted on my tandem (which never gets ridden anyway); I think they look better on it but still kind of silly.
Preliminary rides around the neighborhood are promising. The rack may or may not stay; I'm liking the idea of a big ole basket and a bag up front....