Okay guys and gals, A little color theory / LED / Electrical information ....
Color theory:
Incandescent bulbs emit almost the full spectrum of light. This is done by burning a filament with (voltage * amperage = wattage), which produces a bright glow. That emitted glow includes all the colors of the rainbow, in different strengths. The reason you see green on the instrument cluster is because all the other colors are stopped by the green film. Green is let through.
LED bulbs work by excitation of a phosphor inside the cup in the solid dome, not by burning a filament. This phosphor emits light in a specific invisible wavelength. The (clear type) dome is made of a proprietary material which fluoresces and actually creates the emitted light in a different specific wavelength, which is visible. Different colors have different dome compositions. and dome shape can limit light spread from 3 to 360 degrees centered on the centerline of the dome. The green film is overpowered by the single wavelength emitted from the bulb, though they do get dimmed by the film, especially of the film is a contradictory color.
An LED is a Light Emitting Diode. It is polarity sensitive, and will not work if put in backwards. Turn them 180 degrees in the socket and they will work (if they're not damaged or bad). They typically run on 3.7 to 4.8 volts. A resistor is needed if not included with the bulb cluster. Auto LED bulbs usually have resistors built in, or are built for 12 volts.
While incandescent bulbs (194 size) can require approximately 1 watt of power or more each, LED bulbs are usually less than .2 watt each. The dimming issue is caused by the low wattage draw of the bulb circuit. There are dimable bulbs available. Low wattage can also cause thermal flashers not to flash correctly. Get auto LED bulbs or get digital flashers if this is a problem.
Because of the light pipes in the instrument cluster, 90 degrees spread is probably the best way to go for this usage.