Yes, put a short duration, certainly not more than 2 weeks, maybe as short as 1, and say, "I'm going to order this regardless as to whether every item has a minimum bid." Then, put reasonable minimum bids - I really don't need to see a bunch of bids at levels so low that the auction will never close. The reality is that people are more likely to bid when they know the auction will close and more likely the faster it will close.
I'd also go with buyouts, which goes way back to auctions Potter was doing.
Now, auctions running at the same time do compete with each other, so there is an element of how to sell a bidder on mine than on someone else's. If they all run the same way, not a lot of reason to pick one over another as end prices of goods are largely going to be the same because most stuff has to be at a certain minimum level for an auction to close.
Yes, can get deals on certain things from some auctions versus others as they have different pies. Also because people will throw in augments to cross an arbitrary line at unpredictable times. But, putting aside things like augments, if one person is paying less in one auction, all that means is someone else is paying more in another. Far better to standardize pricing as much as possible so that everyone gets what they want when they want it and we move on to the playing season.