Pete Blair
Nothing to change.
Both NTSC DV Standard 4:3 and NTSC DV Widescreen 16:9 have the same frame size 720 x 480. The difference between the two is that the widescreen has the 16:9 flag that stretches the video for display after encoding (to about 856 x 480).
So, in the Change Settings area, all you do is select the project preset that matches the properties of your source, DV Standard or DV Widescreen.
After you select the project preset and are about to leave that area, you will see the new project dialog showing your newly selected project preset. Be sure to have a check mark next to "Force Selected Project Setting On This Project" before you exit that area and head back to the Expert workspace.
ATR