Im building a miter saw hood that will be ducted at the bottom with a 5 pipe into a 6x5x3 wye with a flexible 3 duct to the blade guard.
I can run the 5 duct straight into the bottom of the box and have a 5 round hole at the bottom. I can fix a 4x10 HVAC boot to the bottom that transitions to a 5 duct leaving a 4x10 rectangle at the bottom.
The labor is a wash. The boot costs $15 which, in the scheme of things, is also a wash.
Objectively, is one option more efficient than the other? What difference in extraction would there be, if any?