I followed a couple videos before receiving my Robo R1+. I went with the dual 40 by 20 fans and ran into failure. I downgraded to single and adjusted my power to the fan. If I set it to 100 the nozzle temp crashes, I have seen this be successful and create outstanding bridging capabilities. I am printing the final parts for my teardown and rewire of the machine for the E3D V6 and XXL screen, and I am slicing with Cura. I have read that dual fans without the shroud works wonders though most use shrouds. What have you guys tried and tested?