The problem I have found with that style, which is very common is that if you can not try it in store, you may find that the tail hole is not positioned correctly or is so big that they may as well have remained naked. I really haven't been very satisfied with the products I have been able to purchase in stores or over the web.
Also, if you plan to leave these on your girl when you are not home be prepared to come home to utterly chewed and shredded doggy undies. Rally is adamant that she is to be a naked girl and strongly feels that no girl should suffer the mortification of underwear. I suppose that is why she chews my undergarments every chance she gets.
An Ibizian hound that comes to agility wears womans control top panties with a tail hole cut out. The woman cuts them so they are just the control top part. Unfortunately, our hounds are a bit to small for that trick.