I think my advice from 08/10 is helpful:

If the save set info is still in the media index, you can actually use it to 
verify the proper sequence.

1) Find the SSID of the spanned save set.

2) Find the correct sequence using mminfo with these parameters:
C:\nsr\bin>mminfo -q ssid=4217039090 -r "ssid,volume,sumflags,first,last"
ssid volume fl first last
4217039090 123456 hb 0 5062035
4217039090 123457 mb 5062036 10095219
4217039090 123458 mb 10095220 15128403
4217039090 123459 mb 15128404 20161587
4217039090 123460 tb 20161588 32060499
Z:\nsr\bin>

3) Simply follow the volume names in sequence.

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