Back to the original picture, is there a cover on one of the pans? One thing I did is cut away some of the angle where the pan sits to get a little more surface area exposed to the heat. Your arch is built so heavy duty I wouldn't worry about it causing any problems. I think I read somewhere when I was making mine that people had cut it so the horizontal part of the angle was only about 1/2" to 3/4" of an inch. With your dimensions you have a 148" perimeter, that will be an extra square foot of surface area and approximately another gallon an hour of evaporation. Looks great.
Pete Nightingale
Lisbon, NH
3 Teenage sap haulers & Plenty of friends and family to restock the beer fridge
2012 1 tap and a pot
2013 10 taps, oil tank evap, 2 gallons of slightly too thin syrup
2014 48 taps improved oil tank evap 3.5 gallons, ouch??
2015 88 taps 78 5/16" and 10 3/16" nat vac 40"x 48" Homemade Arch 13.25 Gallons
2016 100 taps 65 on 3/16 & 35 buckets 17 gallons + unknown amount of maple / Jack Daniels testers