Greg at Specialty Z had a different take from a posting I found. I would think the clutches would be very similar between different manufacturers as long as they are the same type i.e. full face or puck. I mean it's not like we are comparing titanium to lead here.
I just don't know if the differences are really ounces or pounds and if that really would matter.
The post discussed getting the lightest possible for the transmission's sake.