I am going to be using bar trigger shifters. I don't care if they are indexed but my mechanic says he can find indexed trigger shifters that he can make work with an 8 speed Campy rear derailleur. We are using freewheel gear clusters on the rear because we will be using wheel hubs that only take a freewheel, not a cassette.

I didn't describe enough in the original post but I am only looking for an 8 speed derailleur. That narrows down which Campy derailleurs. The ones I listed all came in an 8 speed configuration. I am well aware of the issue with a derailleur pushing the chain between the largest gear and the spokes or pushing the chain off the small gear. We have other issues to deal with here, and the mechanic knows what he can and cannot do. But I can use more than one model 8 speed Campy derailleur, so the idea is to at least know which ones are better than other ones or whether all the models they made in 8 speed are the same quality.. It should not take a differential equation or a massive amount of information about my project to get that information. We want to use a dedicated 8 speed derailleur. This is the maximum number of gears we can run on this frame using a standard hub and wheel that is a 27 inch configuation (please do not post your opinion about the wheels in this thread, because it is not relevant and wastes your time and mine - send me a pm if you really want to say something about it). I don't want to try to make a 10 speed work, etc., and neither does my mechanic. I am trying to get some information for me to shop for used or NOS derailleurs.

So, 8 speeds. Rear freewheel. Possibly a triple chainring on the front (we have to make it work clearance wise with this frame, but assume this is in the picture for now). I already know the gear range allowed by most of the Campy rear derailleurs in 8 speeds is between 26 and 28 teeth. So you don't need that to answer my question. Which Campy models are better than the others out of the ones I listed in my original post? Front derailleur is bought and it has a wide cage to take a triple chain ring. Yes, it is a Campagnolo. Thanks in advance for a straight answer.