It seems that a nice Lionmaster (and they are nice) BB would be the logical and tasteful
choice for smaller curves. A reasonable look involving a smaller loco would look far less
ridiculous than a huge BB MAYBE straining around those tiny curves. (Disney's "Fantasia";
hippos in tutu's; ballet)
But, most of these curve ratings are a tad conservative, I would think, for obvious reasons. Some are not. I have lots of big steamers from all the manufacturers. Some will manage
smaller curves, some will not, it seems. I've tried some on other layouts (I have 072 curves and GG 0-100 switches, so I don't really care). Also, we're not talking NASA-standards here, anyway.
A friend with an 042 GG layout really, really wanted one of the scale Lionel USRA 2-6-6-2 Mallets when he saw mine. A big, but not huge loco. We tried it, and tried it...no go. Jumped the curves, and never mind about the switches.
He bought a Lionmaster Clinchfield Challenger instead. Looks great, right at home on
his layout.