How high have you fermented? I've been too chicken to go into the 90's...
Usually just in the 75F to 80F range for Saison and Trappist yeasts. I am curious to experiment more. I brewed a recent Tripel with M-31 Tripel split with fermentation control vs ambient. The batch at ambient pushed itself up to around 78F during active fermentation and has some off putting fusel characters. The batch fermented in the mid to upper 60F's is very good.