Toller wrote:
Why would dust settling in the 6" pipe matter? A dusty 6" pipe will have
less resistance than a clean 5".



Big chips will also loft the dust if they travel the same path.

I've got 6" 26 ga. HVAC pipe all the way to each machine and directly
into my DC1200, using Lee Valley 6" gates. It's exponentially better
than my old 4" plumbing.

On my Jet DC, removing the 2x4" plug uncovered a 6" outlet. I don't
think a 6-5 right at the machine would be a deal killer.