I would post it in the Classic & Vintage subforum first. Maybe the Bicycle Mechanics.
I’m not sure about you request is for a Sachs Aris freewheel that is 6 or 7 speed. Also are you using Shimano Rapid Fire shifters with a Campagnolo RD. I’m not sure where the Mavic hub fits into this.
I’m running a Sachs Aris 7 speed freewheel with Shimano Rapid Fire and a Deore RD.
As far as pulley wheels, I’ve read Suntour wheels work. I know they are 10t bd. 9t. I’m not sure where the 6 speed Campy FW fits in the equation vs. a Suntour or Shimano UG. I thought all 6 speed FW’s were spaced the same.
John