Which paper should I choose P4 or P6?

I have already choose one paper in optional papers which is P7 but now I want to choose from P4 or P6. First read my situation then suggest me. I was good at F9 than F6 but I want to do ICAEW after ACCA and I will get 1 more paper exemption if I go for P6 but I was good at F9 than F6 and one more thing which that firstly I want to complete ACCA asap.I already take too much time in ACCA, I don’t wanna loose more time to complete ACCA, by choosing F6 may be if I’ll not able to pass easily I’ll waste my time but on the other hand I saw P6 passing ratio is better than P4. Please suggest me.