What's the intended purpose for this larger revolver? Just range use and occasional open carry? If yes to either, go with the Blackhawk. A 6.5 inch would be a powerhouse with Buffalo Bore .357, yet easy on the wallet with the 9mm cylinder. I think a .45 Colt/ACP Blackhawk convertible would do you better as the .45 Colt can be loaded really powerful, much more than .357, but the .45 ACP will shoot just as well, if not better than the .45 Colt will.
A SA revolver doesn't mean you're unarmed, especially a Ruger. Ruger makes really good single actions for the money.