This sounds like it should work. Do you know the resistance of the LEDs? You need to know some of the LED specs before you can be sure of what will work. You can use one of the handy on-line LED calculators (just Google for it) to calculate the proper resistance to add for LEDs in parallel, series, or in combination. I think that if you add a larger resistor, the light will be dimmer. At least, that's what I would expect. So you could achieve a subtle glow that way. I'm going to try some orange ones in buildings at night.