Zen,
I did make some progress with the 067-0521-00 Calibration Fixture on my 547 and need only remove a small dip or 'anti-bump,' if I may, in the first 10 nS of the top of the square wave. Otherwise, I seem to have the requisite 7 nS rise time per the instruction manual and proper squareness of the waveform. Once this is all settled, I will try to tame the square waves coming out of the Tek 106 & 107.
What about the Bodner for the 453? It seems like that scope would be a reasonable candidate while conceding what D. Wise had noted about the waveform so generated by the Bodner. Of course, I suspect that it would be better for me to mend the 106 properly so that I could get the proper square wave for the 453, but as I have never touched the HF response of that scope, I am tempted to leave it alone for the moment.
PMF
PMF