I like it the way it is set up!

My '71 runs Schwinn Approved barends and currently has a 2nd generation Rally RD. Over the summer I took it back to tubular wheels. They however are Hi-E hubs and Faimme rims. I did notice that Scooper's spec sheets appear to show clincher rims with Schrader valves, so this could well be correct. BTW, bikes of your vintage run freewheels, not cassettes. They are very different from each other.
Now that I look at it, I believe I'm actually running a 30T as the large sprocket on my freewheel.