My solution for the "dynamic lookup issue" (i.e. writing data from table 1 to table 2) was using "look up row from table 1" instead of "write data to table 2" which keeps the data in the table 2 updated if data in table 1 changes.
Like Jacob mentioned, you want to write a "unique id" from table 1 to table 2, and then use "look up row" in table 2 based on the unique id from table 1.
That way if the data in table 1 changes, it will automatically reflect in table 2
This is opposed to writing all your data from table 1 to table 2, which is 1-time in nature and won't reflect changes.
