Maple Lady,
My math sucks when it comes to concentration of sugar from 33 gal to 5 gal, plus it depends on your starting percent sugar but I would guess ~8% It will have a lower freezing point for sure but to what degree i don't know. the light bulb would help at least in the flue area, just plug the stack so the heat stays under the pan.
Rob
2014 - 6 buckets, 4 coffee cans and a propane burner - almost 40L of sap and 1.6L of syrup
2015 - 103 taps on gravity. Homemade oil tank arch and a Smoky Lake 2' X 5' hybrid. - 2.66 gallons of syrup
2016 - 101 taps, 550 gallons of sap, ~10 gallons of syrup all dark.
2017 - 138 taps, 225 gallons of sap, 5.55 gallons of dark syrup, still procrastinating on the vac.
2018 - ~150 taps, I lost track of the sap it was incredible!, over 20 gal of syrup, all dark.