So just a quick update for anyone viewing this thread perhaps later, while doing research (as I have been). I reduced substrate to a 1/4 inch, except at the front where I piled it up a bit more, just for looks. I fond a stick of balsa that was exactly 1/2 inch thick and used that as a guide, but found that if i placed my hand over the substrate and "wiggled it" slightly, that was the best way to tell....If I had it right. I'd see the glass of the tank where the tips of my fingers rested, and if I had the substrate too thick, I'd just see a hand print.....maybe that's not so helpful, lol.
I am now getting temps that are too high, which is good, because I can knock that down with a thermostat.