How much is too much: Size alterations

Hi! So my FH’s daughter went to get measured today because we’re ordering her bridesmaid’s dress online. Unfortunately, the company we’re ordering from doesn’t do custom sizing. I know it’s normal to be different sizes, but her numbers came back all over the place. I know the conventional wisdom is to order your biggest size because it’s easier to get things taken in, but she has quite the size gap. Is there a point where it’ll be too much for the seamstress to take in? If it helps, her waist was the bigger size, bust was quite a bit smaller, and apparently her hips are so tiny she didn’t even make the chart. The skirt is the usual flowy BM dress, so I’m actually not as worried about the hip area. I feel like they can cut off whatever they need to there. But will they be able to take multiple sizes off the bust?


Alternatively, should I be worried about the accuracy of the measurements? Even though I’m not getting this dress, I looked up what I would be for reference because I have junk in my trunk that causes large size discrepancies between my upper and lower body. I had gone to a different seamstress, and even my disproportionate self would have fallen between sizes much closer together.