We are using the Place Timber Plate tool with "Rim Joists" option to place floor joists. How do I change the rim joist to the floor joist level so the color and the reports will be correct?
Change the Part definition of the Rim Joist to be the same Part as the Floor Joist Part so the symbology color would be the same or just change the color and level of the WoodJoists_Rim Part to be the same as the WoodJoists_Floor Part. The only way the color will change is through the Part definition. Using the Apply Part tool will also change the Part definition for any existing placed joists in your model.
It is also possible to permanently change the symbology or even the rotation or other properties of a member using the Family/Part Editor.