Actually the less retraction I set, the best part quality I get but with lot of stringing.
From left to right:
LEFT: Retraction: 30mm/s 3mm 210ºC
MIDDLE PART: Retraction: 35mm/s 6mm 205ºC
RIGHT: Retraction: 50mm/s 8mm 210ºC
When I added too much retraction stringing was almost eliminated but I got poor quality (like under-extrusion).
I can try to lower temperature to 200º and print slower, thanks for the advice.
Going back to one of the initial question, how can I set in Cura to avoid starting each layer in the same area and enter/exit the part in the same positions?