I love my herpstat, but as it comes, it only has 3 outlets to attach heating devices to. What is the best/ safest way to increase the amount of heating devices to be attached to this thermostat, of course not going over the wattage. I would like to hook up 6, or 7 cobra mats ( all the same wattage) to this one thermostat. Can I use a strip? Thank you in advance!