I have received a lot of positive feedback, thank you very much! There was one point of concern regarding collision of the screws for the table legs. This can indeed happen if the screws are too long (>16mm). However, long screws don't make sense with IKEA Lack tables, as the legs are only made of thin (approx. 4mm) plywood and the inner space contains a core of folded cardboard.  
For those who are still concerned about the collision of the screws, I have added an additional print profile. The two holes for fixing the table legs are now offset by 5mm in height. 
Happy printing!

I used to put my P1S on a small lack table and it was a little wobbly. With this brackets it is even stiff enough for fast prints.

By looking on the table the screws are not visible.

For mounting I used 16x countersunk head screw (5x16). I recommend to pre-drill the screw holes with a small 3mm wood drill. The part can be used as template.