I use Flexwatt on a helix thermostat in my 60 gallon uromastyx enclosure. I taped it to the underside of the bottom glass with silver foil 'furnace' tape. It doesn't turn on often, it only turns on when the the 160 watt UV basking lamp dies (which is about every 3 months).
The good people at the Bean Farm have instructions for flexwatt use & wiring on their website
Info/Use: www.beanfarm.com/heating/FLEXWAT2004.pdf
Wiring: www.beanfarm.com/heating/Flexwatt_Wiring.pdf
Parallel Wiring: www.beanfarm.com/heating/Flexwatt_parallel.pdf
Attaching connectors: www.beanfarm.com/heating/Flexwatt_connectors.pdf
good luck
benedita