I answered this on the first question but have nooo idea if you'd receive the notification too, so: no deadline! Bidders have two weeks to provide proof of donation; if they don't provide proof within two weeks, then the runner up has the opportunity to jump on their last bid, and donate for the item. That's the only deadline imposed, other than the auction itself. If you're concerned that it may take you some time to get out all of your offerings, just make a note of it on your sign up sheet, and you and the winners can work it out.
Re: Creation
I answered this on the first question but have nooo idea if you'd receive the notification too, so: no deadline! Bidders have two weeks to provide proof of donation; if they don't provide proof within two weeks, then the runner up has the opportunity to jump on their last bid, and donate for the item. That's the only deadline imposed, other than the auction itself. If you're concerned that it may take you some time to get out all of your offerings, just make a note of it on your sign up sheet, and you and the winners can work it out.