
My suggestion would be for the allergy sufferer to visit a person breeding or owning a number of the breed they like.
I have Elkhounds, a double coated (thick wooly undercoat, and coarser top coat) breed. A couple came to visit me as the wife was alergic to do0gs. she spent the day with my then two adults, one who was moulting the other with a litter). I also had two Border Terriers visiting. she had no problems with any of them, or the liberal amount of haor always to be found in my living room. I took her to my friends house who has Dobermans, and a very tidy house. the lady was almost immiediately affected by them, and had found the same with smooth terriers and Dachs. It was definately the dander in her case.
She still has no problems on this score 4 1/2 years after having a puppy, though sadly her husband died 18 months after they had her, and she has been a great source of comfort to her and their young son.