I had some concern about spoke tension and emailed Rolf. They were good enough to reply even though I got the wheelset used.

Question:- I've got a Rolf Vigor Tandem wheelset on a used 2006 tandem that claimed to have 500 or so miles. The front wheel spokes has less tension than the rear. Not just one spoke, it is like this all around. Is this the way they are built?

Answer:- The tension in nearly all our models is lower in front wheel spokes, compared to drive-side rear wheel spokes. Your tandem wheels should be tensioned to around 255 lb/f [front wheel] and 320 lb/f rear wheel, right side].

Perhaps the more important note is this: unless the wheel has suffered damage, or someone has deliberately altered tension - there is no reason to be concerned that the tension has changed from when the wheels were new.

Thought will share this with other Rolf Tandem Wheelset owners.