Digital BW, The Print

My Mamiya 7 puts a lot of space in between the (6x7) negs, so much 
that I cannot scan the third neg entirely and have great difficulty 
scanning the full frame of neg 2.

Is there a way to adjust for image spacing in Silverfast? I am ware 
that there is such an option in Vuescan, but I do not find that very 
userfriendly.

I'm using an iMac, SS120, glass film holder, Silverfast 6 and Jaguar.

Thanks,

Mark