wontonflip
I failed Kobayashi Maru
You DID ask for advice and encouragement :)
I suggest that with the new heater you have a couple or several small wattageheaters instead of a single large one. This is so that if one of them malfunctions, a) theothers wont turn on and b) since it's smaller it will take way longer to make a problem and you have a good chance of catching it before it gets terminal.
I agree on large tanks but its hard to do on a small 10g.
I think there are some 1~3gallon heaters out there for sale, my LFS have those in the pico fresh water tank .
I dont run a heater during the summer and I know several people who live in the hot states also dont use it. I would try running without one and see how it goes.