i've solved all my problems using dual coil at 0.80 ohm using 2 strands of 3.5 mm Silica.
I've fight so many times with my penny v2 when i received, i've read almost all the page on this thread. Got dryvape everytime, with everybuild. 2 strands of 1.5 mm silica, cotton, 3 strands of 1.5, 2...