Cooling Fan Change -- Already
Josh pointed out that the cooling fans, which are from an unused hard drive cooler, are two-wire type, so they provide no information to the PC, and would not be controlled by it; they'd go on and off with PC power. He recommended that I change one of them to a three-wire fan and connect it to the open fan-power port on the motherboard. Then I read the manual on the M4-ATX (it should arrive Friday ), and found it has a fan power port, too.
I could change one or both to three-wire fans. I'm inclined to change only one, and to leave the other blowing all the time. That provides a constant flow of air past the touchscreen, keeping it cooler, and extra cooling as needed. I'd probably use the PSU fan-power port to control the second fan, because it will get much of the heat from the mainboard, plus its own, so it's more likely to have heat issues. The mainboard already has a fan directly on the heatsink, so I'm less concerned with it.