You can find a fan mount for a "Centrifugal fan type" with dimension of 40x40x10 for the version of the extruder from Biqu, the "Biqu H2 V2.0 version".
I also designed an adaptator for an "axial fan type" with the dimension of 40x40x20 used on on the support for the "centrifugal fan type".
I will soon work on improving the files in order for them to be lighter, more resistant, and easier to print !

D12 230 direct drive biqu custom

No

Yes

0,2mm

⁓40%

Personnally i use the "Tree" type support on Cura and the "Normal" type on Prusa Slicer, the "Support fan direct drive v.1" is a bit tricky to print, i advise you to use support, it may also help hold the print in place.

--> I used a layer height of 0,18mm that makes a better surface print /quality but takes a bit more time at printing.
--> x2 Top surface skin layer
--> x3 & x4 wall line count
--> Print at the speed around 60mm/s but it depends on your printer !