I carry a 642 in a Desanti nemesis holster. I used to carry it in my weak side pocket but I now carry it in my weak side rear pocket (5.11 Taclite pants). The back pocket on these pants are large and wrap partially around to my side. The gun fits in the pocket almost on my hip and it is comfortable. Also, the larger pocket it easier to draw out of.
The only thing I would say about a Scandium frame is that when it actually came down to using it in a situation, you won't notice the recoil, but training will be brutal. In my 642+p rounds get painful, I can't imagine a lighter gun with magnums in it...ouch