It is a little bit hard to notice at first, but when you see it, you can’t see it. What you’re looking for is that they’re completely flat, no boobs at all.
if you’re still having trouble with it, you can always go to the sandbox mode and use the boob potion in that to see what every class looks like when they have the reduction bra on.
I hope these little tips help you get that perfect run you’re looking for