Hi gcpdpaul and welcome to the Forum and the world of X10.
I am just curious...... do these sensors need to be 100% flush with each other to operate correctly, or will the max of 1/4 inch off be enough to keep the signal between the one mounted on the door and the one mounted on the molding.
The DS10A sensor has a slight forgiveness. You can experiment with the unit with battries and see the red light trigger. The unit will alllow to what may seem just under an 1" in separation until the light will trigger. This will give some play in case a door is not 100% tight, or in my case a customer may try to come to my establishment and upon noticing that we might be closed but still proceeds to shake the main to door to see if it was open, that has never triggered my DS7000 unit. I also did notice that It should be always wise to keep the two contacts parallel to each other for best result, but a little higher or at slight angle should be fine but don't set them to the maximum distance apart, as time goes and batteries wear down may lead to a problem until fresh battries are them applied. If you search the Forum, look for Dave X10_L and his chair, he used a contact to activate his home automation every morning when he sat on his reclining chair
. There is not limit to the uses of these Sensor/contacts. Good luck and feel free to ask question around here, we are all looking to earn a "Thank for Help" points in doing our part.
BaBaLou.