two pups at once

With the size you are considering, it may be managable.  However, two littermates can have problems (and no problems) as they age and competition for things becomes more common.  Two puppies especially of the same litter are more likely to bond with each other more strongly and in some cases don't develop strong bonds with the folks in the house.  Another situation that may occur, is the dogs never learn to be independent and if one goes and the other stays for any reason you get neurotic reactions from both.
 
A puppy brought in and well raised and trained for 2-3 years makes for a great companion and a good role model for the new one.  You also have the opportunity to build a strong bond with each dog during the puppy stage.  It can be done with two puppies but it sure is not easy, especially if you are thinking competion of any sort in the future.