Custom 2-way fan duct for prusa i3 steel

Iam not so familiar with extruder types. I bought custom made extruder block when i have my printer kit. Unhappily any ed or Jhead serie fun ducts on thingiverse didnt fit to my custom extruder block so ive decided to design my own 2-way fun duct to cool both extruder block and printed layers. It would be fit with 40x40mm standart fans and fit with 16mm diameter and 30mm lenght extruder blocks. If you have similiar custom extruder then be sure that it significantly improves print quality.