Actually they will be a bit brighter using colored bulbs.
The way the colored lens works is to filter out all the other wavelengths other then , say green for the neutral indicator. Using a white bulb, most of the light is filtered out by the colored lens, leaving only the green wavelength light to pass thru the lens.So using a green bulb, with a green lens actually lets more light pass through, thus it is brighter .
Bare, what bulb did you use in your tail light?
TIA.