Diddion

I would like to install tts sound in some old-ish Hornby ringfield locos. However, I have found that these decoders either produce poor running, or, on occasion, get rather expensively destroyed. I would like to use the sound decoder for sound and lights, and a separate one (such as Hornby Sapphire, which I have found works very well with these motors) to control the motor itself. They would have the same address. I do know that this approach does work. However, as my post will reveal, my knowledge is lacking in this area, so I wonder if this is a clumsy way of arriving at a solution. Incidentally, another approach could be to make a consistent, with the lead loco being the tts decoder (so that the functions would all be available from the lead loco). Forum expertise welcomed!