Personally I'd stay away from ammonia solutions. It has been well documented that ammonia can cause 'stress-corrosion cracking' in barel steels (see 'The Benchrest Shooter's Primer for this info).
If you use 'Shooter's Choice' as your bore cleaner, you will get the copper out without the ammonia. (Not 'Shooter's Choice Copper Remover, which has 5% ammonia, but regular Shoter's Choice.)
Hoppe's #9 has a small percentage of ammonia, but I wouldn't worry about a single cleaning with it, or a few for that matter; but if I can pull out bright green patches without ammonia, and avoid the potential risk, I'll stick wth my Shooter's Choice.
Hueco, I was thinking of you this last weekend..was at my local gunshow and saw a brand new #1 .458 on a dealer's table--It looked AWESOME, with that big fat barrel and classic Ruger sights and styling. I'm green as hell with envy.