zombie84 said:
http://www.secrethistoryofstarwars.com/visualdevelopmentofdarthvader.html
This might be of some help. ROTS changes are at bottom. But the costume changed a lot for ESB as well.
Zombie, as always, an excellent article, and the images showing Vader in his various influences and incarnations are great.
At the end of the article, you discuss darthblade's article on Vader's chestbox and its possible Hebrew meaning. Although darthblade's site has disappeared from the net, I used (with his permission) some of the photos from his site in my own analysis of the writing on Vader's chestbox:
http://erikstormtrooper.com/sithprophecy.htm
To sum up, I concluded that the writing was Hebrew gibberish. The writing changes from ESB to ROTJ (and then later it changes 2 more times for the Visual Dictionary and the tour suit seen at the Magic of Myth). The Hebrew letters are often flipped upside down or cropped. And I have yet to get in touch with anyone who can REALLY read Hebrew who's willing to go through the various versions for me.
The chestbox for ROTS, like the ANH version, does not have any writing. Since most aspects of the ROTS suit seem to be based on the later ESB and ROTJ look, I'm guessing the lack of writing was intentional. I doubt it was for visual consistency with the ANH suit.
Not that anyone except me cares about any of this ;)
Anyway, using Hayden in the Vader suit was a bad call on Lucas' part. He's just too small. Even if Lucas has a thing against Prowse, he could have easily found someone of his stature. In the end, it comes down to laziness, like most things in Star Wars these days.