EDIT: The best way to secure the duct to the bracket is an 18mm long piece of 6mm (or 1/4") aluminium bar tapped for the M3 bolt in the middle (see pics). Works brilliant. Credit goes to 58webbing
Since I installed my Heaxagon hotend I've been working on a low profile fan duct design that could also be used for the E3D and other hotends. This design easily fits with the Hexagon, as shown, and is angle adjustable. The bracket attaches screwless to the X carriage, front or back.
I'll upload some variations of the bracket with the fan mount at lower positions for longer hotends in the near future.
To install, drill out the 4 fan mount holes to 2.5mm. Then you'll need an 8mm, or 10mm should fit, M3 bolt for attaching the fan duct to the bracket and 2 to 4 10mm M3 bolts for attaching your fan to the fan duct, assuming your fan is 10mm high with counter sunk bolt holes. I used 4x10mm M3 bolts for the fan and 1x8mm M3 bolt for attaching to the bracket. Do a dry fit of the bracket + fan duct to get your angle right then nip up the fan duct attachment bole and attach your fan, then clip the assembled unit to the X carriage.
Printed in PLA, 0.3mm layer height, 2 perimeters/top/bottom, 25% infill. The bracket requires support, with Simplify3D use 1mm resolution support at a 30% angle (not overhang angle).