In my case, on big prints covering the whole build plate it happened that the original fan design was hitting the bed connector.
This version of the dual fans solves that problem being shorter by 3.2mm on the height.
24-12-15: added a taller (by 2mm) version that in my case still doesn't hit the bed connector. YMMV.
Print with supports (light) at 10degrees as laid out in stl file.
single version made in DS Mechanical and sticked together in Tinkercad (missing mirror option in DSM - grrrrr)