I thought I should post some information on how to add to the list of standard duct sizes that the duct pop-up allows you to choose from. Because I am only (at this time) making changes to the list of ductwork, not to all the fittings, it will ask for verification for creating a "custom" part .
Go to: Cad Manager/Content editing/Catalog editor
Go to File and Open the Duct US Imperial.apc catalog: ???
(depends on your server and filing system, most likely here) /enu/Aecb Catalogs/Duct US Imperial/
Expand the shape you want to work on (I did rectangular and then round)
Then expand Ducts/Rectangular duct/Constant lists
(For round: Duct/round duct/constants list)
Scroll down to the bottom, select a cell, and then hit enter on the last row items.
This will start a new row.
You have to do this for each individual cell, it does not just work for the entire row.
Once you have added and/or edited the sizes you want click on File/Save.
Then close out of the pop up.
Now double click on the catalog and regenerate the "duct" catalog.
You size changes/additions should immediately show up.
If not you can close out of ABS and get back into it and they should show up.
This is not tied to just one drawing, it should be accessible to all users with new and existing drawings.