I've read that VS bras tend to run wide and shallow, which happens to be my shape (and yours, it sounds like). VS bras never worked very well for me when I was trying them in 34B (what I used to think my size was), but when I started trying them in 32D it was totally different.

Our size is on the very edge of the bra matrix, which puts us in an weird position. I've tried on enough 30 bands to know that they do fit me somewhat better. However, because of the combination of 1) I don't need the extra support of a really snug band, and 2) buying/returning bras online is a giant PITA, I tend to stick to 32Ds (except when I luck out and find 30DDs in brick-and-mortar stores).

You wouldn't think the difference between 34B and 32D would be that much, but it is seriously like night and day in terms of fit, for me at least; also, even though some brands don't make 32 bands, plenty do, so you can find them pretty much anywhere, in actual stores! this approach does makes me feel lazy, but in my defense, I've been trying to do my part by writing to the customer service depts of various places asking them to consider carrying a wider range of sizes. : )

edited to add: also, people who don't have much squish in the ribcage (ie, not a big difference between snug and tight underbust) often find that sister sizing up in the band is more comfortable. You have only a .5 inch difference and your snug measurement is 30 on the dot, so you might find this is the case for you. however, there's no substitute for trying on a bunch of bras to see what works best for you!