That's a good point. That's why 3711 would take a given wort down to 1.004, where as US-05 may stop at 1.010 in the same wort. So, they'd be 50/50 down to a certain gravity, then 3711 would keep chugging.
Maybe I'll split the batch and do it both ways, then report back here.
Update on splitting WY3522 and Belle Saison:
This was a rye saison with 50% 3522 slurry and 50% BS slurry, each about 50 mL. Pitched at 80F and temperature in the basement was 79F, so it is reasonable to assume that temperature of the ferment reached at least 85F. At the start of fermentation, the esters dominated, but after about a week, the whiffs off the airlock were distinctly saisonesque.
OG was 1.054 and FG was 1.000 after 3 weeks of fermentation.
Flavors at bottling were dry up front, but with an estery, peach-like finish from the 3522. I would say that the esters were a bit more dominant than were the typical BS saison flavors.
I primed this, targeting 2.7 vol with DME.
I'll update this with the "from the bottle" tasting notes once carbonation is finished, probably another two weeks at least. Right now, I can't tell if I will like this beer as much/more than a straight saison.
UPDATED: 10 OCT 2016 - I would say that the esters are somewhat inappropriate for a saison style. They are strong on the nose. Very peachy, and the taste profile goes from peach to saison yeast (BS) back to peach in the aftertaste. That's not to say that this is a bad combination, I am leaning towards the temperature being just too high for the 3522. I may try this again once the basement gets to around 67F (soon).