The Mann of the Moment“As many couture jewelers could attest, attracting a young engagement customer can be a challenge when you’re perceived in the marketplace as being ‘high-end,’?” says Nancy Mann, CEO of Mann’s ­Jewelers in Rochester, N.Y.To overcome that obstacle, the store recently held its second annual Platinum Proposal Contest, teaming up with a local radio station, a performing arts center, and Plano, Texas–based bridal brand Sylvie Collection.Using a mix of social media, radio commercials, and street teams (composed of radio interns in bridal attire) distributing flie