after many test I've ended up on a cooling mount on both side with just one blower, never liked fangs so I made this.
-air round from both sides
-the blower takes the hair not from the hot end side so is sure cooler ant there is less pressure
-the blower is firmly hooked with the mount so creates less vibrations from my other mounts, less noisy
standard and fully adjustable with 2 screws.
as my other mod I suggest to use : https://www.thingiverse.com/thing:2612897 to cool the heatsink but many other mod that screws with it will work as well
material suggested petg or abs.
-the best way for a clear duct would be the support just from the bed, and change the density till it will support the two bridges or add a manual support