You can use the DCS TIU variable outputs and run conventional using the handheld to vary voltage like a transformer handle. If you're running in DCS via the variable channel, voltage needs to remain above a threshold (16 volts in m experience) for DCS to operate properly on a loop powered by that channel.
You can isolate the three loops at the switches, run them via different TIU channels, and have a DCS engine running on one loop and a conventional engine via variable voltage on another.
You cannot run an engine under DCS on the same loop with a conventional engine unless you want the conventional engine going 100. In order for the DCS engine to function properly, it will need a minimum voltage that will leave the conventional engine running high speeds.
The book you mention is the DCS Companion. Volume 3 covers most things, and the DCS WiFi Companion is the book to purchase if you plan to run via the app rather than the handheld. Either version of the book is on Amazon.
