I think the dividing line with VS is smaller band sizes. If you wear 32's and up you can find a fit. If you're a 30 or 28, they're going to put you in what they have, which isn't going to fit. It's becomes about making the sale :/

Have a trusted friend measure you. Be sure to lift UP the girls so that you get an accurate band measurement (this prevents you band from riding up because if you don't do it your band size will be too big). Then measure again wearing a bra the fullest part of your bust line. In both cases make sure the tape is straight. The measurement you get from lifting up your breasts is the band size that's the numbered part of the bra size. Say you're 32 inches around, then the band size will be 32C for example. The difference in inches between your band measurement and your bust measurement will give you your cup size. The tricky part is that cup size will vary depending on whether you are larger than a standard C cup because American makers only make a 1/2" difference between cup sizes above C where as European brands give able 1" between cups so it makes buying a bra a pain because while the letter and number may sound the same across brands the size is not. I just remembered that Herrom.com has a universal sizing calculator that should be helpful because it's based on the difference between your bust and band size -- but it is only helpful the difference between your band and bust sizes produce a D cup or larger (which i think is a difference of more than 4 inches.

Day Vies, I had to laugh out loud at lifting up the girls . . . she's asking us smaller sizes for tips. I don't think a single one of us could lift anything! Just goes to show, there are challenges at both sides of the spectrum.

You got some great advice. I have some bras that work but I am not the happiest with them. I will also check some of the ones that people suggested.
Sorry that I cannot recommend anything at this point.
Have fun on your trip and good luck with the shopping.

By the way, RueLaLa is having a sale today on the Simone Perele bras. I was able to pick up the ones I mentioned for $50 and $40..

Wacoal Petites work best for me. I am broader in the back so I need cuts that are closer together and Wacoal has many styles for this fit issue.

I am def. not on the small spectrum (32E), but I also recommend Nordies, because they are the only place that have a huge enough variety, and the salesperson gladly bought me bra after bra after bra to try on and reject.

Personally, I don't rely on other people's measurement and instead read up on measuring bras - I think herroom.com has a good guide on how to measure and what to look for. Then, I go to the store and keep trying on bras that are:

1. one band size smaller and 1 cup larger

2. the correct size

3. one band size up and 1 cup smaller

And eventually, I find a few I like and that work. Then I record the model number and the brand before it wears off in the wash. Then I hope to find them again when I need more bras, and of course that never happens!

Also, sports bras: I do burpees in the changing room - if nothing plops out- I am good to go. I do bootcamps and really cannot be adjusting the boobies every 10 seconds.

LOL! DayVies for lifting the girls up. Thanks for some great advice there. I will use this calculator before going to Nordies and compare the difference in how they size me up.
Mo, I am thinking about to get fitted at Nordstrom and then at VS to see how they compare and which one fits me better.
grandfashionista and Deb, thanks for your helpful suggestions!
Disha, that is a great strategy. I am definitely going to use it.