I have used the WY3711 on two saisons so far because it is supposed to ferment at somewhat lower temperatures than the 3724. It has worked beautifully and imparts a deep yeasty saison character to the beer. Both times it has attenuated very low- SG1.002 and 1.003, yet the beer has great body and a very deep flavor and great aroma.
Not sure if you are looking for that characteristic estery flavor typical of strong Belgians like Duvel or Houblon. 3711 will probably not give this. I don't have any experience with the 3787 or 1388 (Belgian high gravity and strong ale strains), but you will probably find a lot of threads if you enter them in the search box.
You will end up with a beautiful saison with 3711, but be sure that is what you want.
