[Slothie]

Having read most of the SC/MP documentation I could find it's clear that National didn't think the timing relationship between XOUT and NAFS/NRDS//NWDS etc was important to document. For your purposes I can understand why you need to know this however. I doubt that Karen's PIC14 is going to help because while it is cycle accurate she makes no.claims to timing a accuracy down to the microsecond.
Probably the best you can do is to make measurements from a working SC/MP processor (perhaps using a variable frequency oscillator to see how the clock frequency affects timing). You probably wouldn't need more than the processor, some pull down resistors to simulate a 'NOP' instruction and perhaps a tel gate to get the instruction fetch flag as a trigger so you have a stable waveform to trigger off. And a scope or logic analyser, of course. Its possible someone here could take measurements if you sketch a timing diagram showing the timings you need.