Hi. I live in Copenhagen but I guess that´s no good. I use lace and show my hairline. I just ordered the thin skin (0.03) to test it. I ordered both units blond and is doing the coloring myself to obtain best results. For lace it really depends on the knots being completely invisible. Test your lace system by puttin it under a white piece of paper. The knots should at most be very light orange to the point where they are hard to see. You need to test this in daylight, as the soft ligtning from lightbupls contain soft orange light (that way you wont be able to see the orange color that you are looking for. Also you can test the hairline and knots by attaching the unit to your arm og leg) Have never done this but why not. That way you´ll se wether or not the hairline is disappearing.