[Jonestead]

Thank you again Richard for pestering me...oops i meant to say your excellent translation of my lack of clarity. You are absolutely correct that my bay doors are solid with no vents. The original SCS units were vented thru the floor (see pix)
There was considerable discussion about cutting/adding louvers to the doors for exhaust however I was  very uncomfortable cutting those doors...best intentions sometimes don't work well. After noodling on it for quiet a while, the ducting was fabricated and voila, minisplit now breathes like the original SCS installation with benefit of radius to maximize flow. If heated exhaust from minisplit or generator mixing with intake is ever an issue, similar radius duct will fix that easily