your plan sounds fine, you really dont need a heat light in there. but if you want to and you do be sure it is very secure, we did have a fire in our coop it didnt get out of control it happened in the walk way where there arent any shavings, however it did burn a hole right threw the floor. and we happened to go out and find it so we got lucky if we had not gone out there the birds would all be dead, so it is very important to have it double triple fastened.