Hi Smithy,
Thank you for your answer.
I will change the minimum layer time from 3s to 10s.
About the printing temperature I've followed the guidelines from FormFutura. They advice temperature from 240°C to 260°C and I've tried 240, 250 and 260°C. I will try again at 240°C.
I've enclosed the printer in a chest made from heat insulation material. I felt the temperature inside was much hotter than the room temp so I will lower it down.
I've set the flow to 106% following guidelines from FormFutura, I will set it back to 100%.
I will try again with the settings you advised and keep you updated.
Thank you !