Trying all the different permutations on multiple effects to exactly match what you did before could take an eternity. Quicker to re-record all the vocals (with the new 12 lines added) then apply “stairwell” effect. [a “stairwell” effect could be echo/delay followed by reverb(eration) ]. Save a copy (WAV format) of vocal without effects just in case you need to add more lines later.