It worked like a charm! Not a drop of mud splatter and I went through plenty of mud and puddles this morning. The drive train took some though - I guess a mud flap is in order.

The back tire is 26 mm by the way, so the 1 3/8" strip overhangs the tire by 4.5 mm on each side if I have it centered perfectly. I'm probably 1-2 mm off so the same size strip will likely be good for up to 700Cx28 if you're more precise.