Great idea about the back to back mounting!
I have used the test strip material over the years to get an idea about actual temp of the press vs. the indicated temp on either the dial or the thermometer. They allowed me to quickly get an pretty accurate read on the thing. I always found MT5 worked best for me about 180... I always used the ColorMount at lower temps and let the cooling plate do the actual bonding. That saved heat damage to color prints and kept the prints from that embarrassing trip to the floor from your mount during presentations...
Great heads up about the dreaded tacking iron too!!!