Not sure what the specs are but, I think they are the same for the irons is they all have the same shaft. There are different sizes for woods, hybrids & Drivers I think ? I could be wrong, it has been known to happen before :-)

Titleist has used an all black ferrule about 7/8 of an inch long since the late '90s. If you go to a reputable component supplier like The Golfworks and order the black taper tip iron ferrule, it will work well and look extremely close to factory depending on your skill in finishing the ferrule after assembly. The ferrules will not have the exact outer diameter of the hosel and must be "turned down" as we call it to create the final factory look.

Golfworks model 66TI is similar if not the same as what you will find on factory built Titlest irons and Vokey wedges.

I'm working on reshafting a set of AP2s myself. It looks like the AP2s are supposed to take collard ferrules. I have the ferrules you mentioned, the 66TI and they do look similar, but there's no collar. How did you guys get around this issue?

Josh