to answer your question....there is the 3mil tape which does give an undetectable hairline......
but i have to agree with others...your hairline is not attached up to the edge. it is clearly off your scalp. perhaps this is what you want and you only have the tape attached behind the edge of the lace but not right to the edge.
i cant see how it is the lighting because there is an actual gap between your scalp and the piece...

i didnt include the corner of the hairline on the right side of your screen because you stated you havent any tape there