Laura, I just wrote what basically amounted to a blog post on volume over on the boho thread (I made sure Angie approved everything I said so I didn't give totally wrong and bad advice). I don't know if you didn't get around to reading it or if you did read it and it just wasn't clear enough. I'll try and summarize:
-Tops must be TAILORED even if they're not structured. They should fit perfectly in the shoulder and arms and gracefully fall away.
-Not all volume is created equal. You might have to try lots of different styles and experiment a lot with how you wear them. Voluminous tops are like any other, with a variety of necklines, details, and varying degrees of volume.
-No volume anywhere else. I think we all know this by now. If you wear wide leg pants or a fluffy a-line skirt you'll look like a clown.
-Volume doesn't necessarily mean something big and puffy. It might just mean something that isn't as structured around the waist and has a more relaxed fit.
I think the reason I like volume so much is because voluminous tops are fitted from the shoulder, which is one of the smallest and daintiest parts of my body. The rest of the top just floats away from my problem areas. I think it causes the illusion that under all that fabric lies a tiny waist because I'm imagining my waist in proportion to my shoulders, and based on my bone structure and shoulders you would expect my waist to be very small.
So in some backwards, roundabout way, volume does give me a tiny waist! I guess no one puts quite as much thought into it as I do though. That said, I think the only body type I'm not sure about is the inverted triangle. I have mixed feelings. On one hand, I wonder if all the volume elsewhere will detract from the shoulders and make them look smaller by comparison. OTOH, I wonder if there is too much emphasis on the shoulder. Maybe Angie can clarify. My guess is that inverted triangles can wear volume but they'll have to pay extra attention to sleeves and necklines.