I recently played around with the Teresa character, that I bought up at the Platinum Club, and it comes with a nice Pose entry that resizes V3 clothing to Teresa. That's the first time I've seen something like this and am curious what it's doing. I've only tried the pose on a few clothing items, but it does a fairly decent job of making them fit.

Well if the clothes have morphs for shaping the clothes then the pose just sets those dials.

IIRC Teresa is a "petite" character right? There's one here called Kashmira (which I love btw) that's also a petite character. I'm assuming they both work the same way--the pose file sets any morph dials as appropriate but also scales the various clothing parts to match the scaling changes in the figure itself.