One additional suggestion: since you say you are using twin-coil machines you should use a capacitor discharge circuit to prevent your switch machines from burning out.
The idea is that when you throw the turnout, this circuit shoots a burst of electricity down the wires to activate the turnout motor, but not enough to burn it out. If you use a push button or a toggle switch and hold it open too long, you can burnout either the switch machine or the switch at the control panel.
I saw this happen at a model railroad club where I was a member. As was typical of Murphy's law, this little problem didn't manifest itself until just an hour before we had an open house.
Then one half of one of our tower's went dead.
BTW, if you need a circuit diagram, I can help. Based on the earlier kindness of strangers on this very discussion list. I have a circuit diagram.
Clifton<BR>Chief Cook and Bottle Washer of the LaZ & E RR, (known locally as the Lazee Boy Lines)