Forget the resistor across the outputs, use a .01uf 50V capacitor. That give the triac the load it needs to fire, but doesn't consume power all the time. This is how the ERR products handle the lighting outputs, and I also do the same on my Super-Chuffer lighting input line.
Obviously, you'll need a series current limiting resistor, for TMCC LED's, I use 470 ohms 1/4W. Finally, the positive lead of the LED goes to frame ground as the TMCC lighting output is negative in respect to the frame.