Spindle type will depend on which bottom bracket you choose. If you
really want a Super Record bottom bracket, it will be a titanium spindle with pressed-on steel races and will use 3/16" balls (rather than typical 1/4" balls), and cups with races ground to use the smaller ball size. These bottom brackets are fairly scarce, expensive, and have a less-than-stellar reputation. The spindle will have threaded studs to take nuts, rather than bolts, and for your frame should be marked 70-SS.
But most bikes marketed with Campagnolo Super Record groups didn't use the fancy-pants Super Record bottom bracket, but instead used the old, reliable Nuovo Record bottom bracket. These are far more abundant and less expensive than the titanium bottom bracket. Again, you'll want a spindle marked 70-SS.
Here's a reference guide to Campagnolo bottom brackets:
http://www.os2.dhs.org/~john/campy-BB-specs.pdf