I always boil with my lid off. Especially when I'm trying to boil down 6.5 gallons to 5 or 5.5. Also, if you start to get a boil over, spraying it with a fine mist of water usually stops it.
Thanks! I watched a couple of YouTube videos on other peoples builds. Luckily, I had most of the parts at my job. I'm going to install a speed control tomorrow. Turns out, a speed control is more of a necessity than a feature. Sometimes it takes a few tries to get the stir bar spinning.