Avoid CA' s for clear parts due to the "frosting" effect it can produce. My personal adhesive choice for that that is Micro Krystal Kleer that is water soluble and can be applied with a fine brush in very small amounts to tiny parts. It dries clear but still requires careful application to avoid squeeze out onto surrounding surfaces. I brush it in very thinly and let it dry a about 30 seconds before attaching the part.