Work on my exhaust upgrade has begun. The plan is to use a 10in x 4in x 6in register box with a 90° bend connect to (eventually) rigid duct work to a 6in in-line duct fan at the end of the line and ultimately to this vent.
This is the state of my mod far:
removed original fan and vent flange
drilled holes to attach register box
attached register box with M5 screws
sealed entire union (inside and out) with metal tape
For now, I am using mostly semi-rigid duct until I can learn to size the rigid stuff. The exhaust fan is a Vivosun 6in inline duct fan. Supposedly pulling 390 CFM.