STAGE 2, I'd say if you want it and have the money, get it and don't worry about it. I suspect the engineers at Ruger have tested it to destruction and are confident the decrease in top-strap thickness doesn't compromise the strength of the revolver.
In the event of an overloaded reload, Ruger isn't liable (you do read the print in the manuals that says "Do not use reloaded ammunition", right?"). And in any event, a load that takes apart a Clapp-edition GP-100 would probably have taken out a regular GP-100 or Blackhawk too. Contrary to popular opinion, Rugers aren't indestructable, and if you're shooting loads that are wearing out a .357, you should have gotten a .44...
