It is usually said, that “text” paper (as F4) is well combined with “number” paper (as F6 or F7). I have passed F4&F5 during one sit and I felt OK. (F5 is 50/50 “text”/”number”)
Yup i agree F4 and F6 thats what im doing and there are good because one is word based and one is numeric based.
I found found F5 strangely tough but im be hopefully passing the both this year.
Plus if you are looking at taking the UK version of F6 you should take it before June as this is the last sitting of the current sylabus, then it changes for 2014 december exam