Thanks to Jeff Broderick @brdrck at https://bantam.design/ for the great modular ducts.
I have made a mount for the BigTreeTech Legend to improve the printing capability.
I also used the Modified Banta Mount I made for my Anycubic Curon https://www.thingiverse.com/thing:3869642
You can find More duct options for other fan types on https://bantam.design/mount
I went through may iteration and this is the one that worked for me.
Resolution:
.02
Infill:
10