The 270 SAA ought to be a terrific bullet against anything on two or four legs likely to be encountered in the lower 48, cast at about BHN 12-15 and driven to about 900fps with any of the three powders above.
I'm also thinking it'd be a good bullet for GP up in the interior too. I'm laying in supplies and equipment now for casting after studying under the expert tootledge of one of my buds who casts. The RCBS .45-270-SAA and the Lyman 255gr Thompson design are the two I've settled on for now.
For my purposes out here on the AKPEN, I'm still going to stick with the 330gr Stoners.