I have a CT26 with the VA separator and a WorkCentre all stacked up together, and it works like a treat.
I also have a VA separator on my OG CT-Mini, which I tend to use for general cleanup and as a much quieter shop vac for cleaning out the cars.
You really only need the Auto-clean on the 48 if you're going to be using it for drywall work.
Even then, the 36 auto-clean is lighter to move with a full bin, and I'd imagine anyone using a CT for drywall work is doing that semi-mobile, as there are only so many times that one can re-rock a workshop.
The 36 AC comes with a hose specifically for the Planex, I don't know if the 48 AC is the same way.