I’m sure the entities I evoke will understand that I have to keep looking back and forth for the first few times, but I know eventually I won’t need it anymore, as lucifer use to tell me: “persistence creates perfection my son” 
I would practice the technique first, before you start calling any entities.
I did another method of evocation when I was on belial’s gate, But I want to try EA’s method with amaymon, which is why I bought his evoking eternity finally, maybe I’ll like his method better, it’s been giving me a huge magnetic pull to buy that book, my theory suggests that lucifer possibly wants me to try some other way. I feel that’s why I got a magnetic pull towards his method, also because I hear it yields very positive results!