Gunbroker Opening Bid Philosophies?

Looking at letting a portion of my collection go and GunBroker seems to be my best bet to list them in batches. What's everyone's philosophy on where to set your opening bid? I don't want to be excessively cautious and drive away potential bidders by putting my desired price (though realistic) as the opening bid, but do penny options really yield that much additional interest if you're not one of the big names? Thanks.