Jim,
I suggest you purchase the OGR Video Guide to DCS, Rich Melvin in the OGR video has Jim Barrett do a great video teaching job, on exactly which Toggle Switches to use, and exactly how to install them in you layout. This particular back shop segment is the very best Toggle Switch instruction I have ever seen done, you can watch the video as many times as you need, to understand exactly how to install and run the Toggle switches. Then sit and read Barry's exacting instructions, in the DCS O Gauge Companion Book.
PCRR/Dave