Proper attire for 50 year old woman to give public presentations

I spend several weeks a year giving presentations to the general public (usually families) in several Chinese cities. Most of the female attendees wear dresses, but I am overweight and difficult to fit in dresses. Are black dress slacks with very nice "statement" jackets okay for presentations? I've read that larger jewelry is not appropriate, but I would like wear larger necklaces. Also, should I avoid wearing white or any other particular colors? Thanks so much for your help!