So this is probably too late for you, but maybe can help someone. We have a local, professional auctioneer that does our live auction, and is more than willing to help us figure out if items would be better in silent or live. But he's also a parent in our school, and donates his time. I personally think it makes all the difference to have someone who does this for a living -- he's very good at convincing people that they want to keep on bidding, and a little humor goes a long way at these sometimes lengthy events! They know when to push it just a little and bidders keep going. And if you have a decent number of items, they keep a fast pace to get through your items without losing profits.