I took your collective advice, went to the Title Nine website, used their measuring chart, and ordered a garment with underwire & racing back. The result has enough straps, hooks, and cross-bracing that it ought to be made out of Kevlar and stop bullets. However, I was comfortable and the runway judges approved.
Mission accomplished.
Virtual Brush Box 
It’s tough being a girl but it beats the alternative!
Really, I’d much rather have to deal with the girls than the, er, boys. Ew.