Hi again,
I do not yet know what BSF means for wire (for threads, it means British Standard Fine), but I do know that the wire in use today is significantly stronger than what S&S listed. See here:
http://www.sailingservices.com/stand...d_1x19wire.htm. And here:
http://www.riggingonly.com/wire.htm#WIRE. 9/32" for your uppers. Smaller for the lowers and backstay.
Fair leads,
Brion Toss