its the initial cure and anything above 60 should work with right amounts of mekp, the cooler temps after initial set will prolong the cure but it should be fine, i did mine at 60 and it dropped to 50 overnight and it never caused me a problem. if it dropped to freezing i wouldn't know how that would work but you figure if initial cure has gone off the rest is just slow cure.
not sure i would use a electric heater around those vapors, i wouldnt worry about it or call resin mfg and ask them about temps to be sure . heaters scare me around vapors lol.
I stopped counting $$ years ago! You go boy!
And the waiting is the hardest part......a little Tom Petty for ya!!