When you created your Custom WT, did you generate a Transport?
If not, you probably only did the test (the default setting), but if so, you should be able to see the tables that were impacted when looking at the objects in your transport. (Note that a transport may not be generated in a Sandbox environment).
Actually, when doing the WT Copy Test, you should be able to see the tables that will be impacted when doing it "LIVE", such as in the following screen capture
Note that this was a "Test run" but the message for the entry in table T512 still says "Entry was made". Do the Test Copy again, and compare the result with the objects included in your transport.