@Hudson, there is some good news on the DCS/DCC front. All of the MTH locos with PS3 have DCC bult in already and they even automatically detect the the signal... AC/DC/DCS/DCC. That is a major reason I am looking MTH PS3 locos.
That is very good news about the DCS/DCC switch but are you sure? I have a PS3 locomotive, I admit it is one of the early ones, but it does have the DCS/DCC switch on the bottom of it. Hey, I really hope you are correct about that because that would simplify things greatly.
I look forward to seeing your layout. From your description it sounds like it will be really nice.
Wow 23! That's a lot of conversions. If you can, please post some pics of the finished product.
I know there were some threads about converting to fixed pilots on the 3RS forum but I am very interested in your way of doing it because you are working on MTH engines. That would be very helpful. Thanks for sharing.