You're getting ahead of yourself. Be sure that your readings are like I said in the post above, so now would be the time to add the extra LR. Let that settle in like above then do your 50% water change. It would be okay to do them in 5 gal jugs now, but the sooner you start to do it correctly the sooner things will go your way. No rush, take your time, while your tank is doing it's thing it's a good chance for you to catch up on your reading.
1) ammonia and nitrite both have to go to "0" test water
2) check to see that nitrate has peaked, test water
3) now do the big water change and yes test water again
4) all stable add clean up crew test water again
5) all stable again add a fish.....test water
6) all stable do 5 again