I think you're looking for something like this:
Code:
positionOffsets = [x,y,z]
rotationOffsets = [yaw,pitch,roll]
grabLink = viz.link(hand,object,1)
grabLink.preTrans(positionOffsets)
grabLink.preEuler(rotationOffsets)
You mentioned in your question that you want to offset the position, but in the piece of code below, there is a variable called rotationOffsets. You can offset the rotation of a link with link.preEuler() and the position of a link with link.preTrans(). Both are described in the code above. Hope that solves your problem!