I normally do the auctioneering in my leagues in addtion to managing my own team. Make sure whoever does it stays consistent with the countdown for obvious reasons. Being the first auction I'd plan for 4 hrs minimum. If you want to speed it up, announce before it starts to keep side conversations low so those interested in bidding can hear and you don't get bogged down with "how much he said?". And just like in a draft, stress to your league members that as much as they can help it, have someone ready to put up for bid.