I use the Dew-not heater straps and so far am very pleased.
http://www.dew-not.com/Order_Form.htm
I started trying to make both discrete resistor types and nichrome wire ones and was unhappy with the direction both were going. A small range of straps and all the smaller optics are fine. The only issue so far has been keeping a 10" corrector plate dry all the way across, about 1/2 dry in bad conditions. Hopefully some shielding will help with that.
Bob