Red flag. How big is your ball? They normally like 2 identical hides. That way they don't have to choose security over thermoregulating. TThe sound shouldn't bother the snake unless it rattles the cage. As for having them set up on either side of the tank, I personally would move them to another location. Welcome to the forum and the new addiction. There are a lot of people who have a vast knowledge of balls and other snakes on here. So as long as you are open to suggestion, this is a gold mine for information. Happy herping!
EDIT
I didn't see the gauges till I posted I would go with digital thermometers with probes and a digital humidity gage. They sell accurites at Walmart for 10 bucks and it is a thermometer hydrometer all in one.