Hi Ron,
You are right that drawing a transparent led is really drawing transparent pixels - which is not the same as "undrawing" the opposite led state pixels.
I had not tried to make a tri state led - sounded interesting so I figured I'd try it.
I managed to make two overlaid leds look as a tri state led.
I've shipped the sample screen set to you via direct email.
BTW, for the jog mode case you mentioned, I believe that is really a 4 state conditions that you will want to show visually. The 4 states are:
1) cont jog
2) step jog
3) MPG jog
4) no jogging - all three mach leds (14, 15 and 57) will be off if jogging is disabled, hence the multi state led will probably want to have an "off" visual state too.
Dave