I have had one going on my plants all summer to keep them cool
me too. i have three fans: one in front that oscillates for circulation, and two in back for exhaust. when the door is closed, the plastic on the GH sucks in, meaning i have created negative pressure. i'm hoping this will expel some of the mold spores.
i did the pen torch on branch rot last year, and although it seemed to stop the spread externally, i'm sure that it helped nothing internally, as the buds up the branch were all suspect. FDD suggested some product that would be used for repairing/covering a scar in tree branches. he said it would only buy you a little more time though. can't find the product on a quick google search, but it looked to be some sort of tar or resin.
in the end, the best bet is constant vigilance. look for the tell tale signs of mold: twisted, deformed leaves among an otherwise healthy looking bud usually point to bud rot within the bud. remove them immediately. do a check every morning on all of your plants.