67 feet of active element will give you a 20 degree delta T. Loops shouldn't be more than 170 feet. The 007 can handle this.

You are wasting a lot of fuel running the boiler that hot, plus, like johnsp said, that high a temp leaves no room for error. If you are short on element, and you are maxed at 70 feet of it, then add another seperate loop. It would be cheaper than throwing $ at the fuel co.