There must have been many variants of the Spence Wolf adaptor. Mine (Wool Jersey - '71 Cinelli) was a double cage made of polished stainless steel where most of the others are chromed steel. It was put on the bike when purchased at Cupertino Bike Shop in '71. It shifts well with 28 on the back because I did the Death Ride with it about 10 years ago with no problems. The one annoyance with the "all Campy" bike is once the chain is off the three large cogs of the freewheel, the chain drags on the bottom of the front derailleur cage if using the 28 front chainring of the TA crank set. It's then time to change to a larger gear. One to one gear ratio is quite a luxury.
Ted Trambley
Martinez,CA USA