If a chocolate seems to consist mainly of wafer (eg kif-kef or Kit-Kat) should one say "Mezonot?" I assume that if there is doubt concerning whether there is more chocolate or wafer one should say "Shehakol"?

Though there is not universal agreement on this point, it seems the most common positions that if the majority is chocolate, it is "Shehakol" and if the majority is wafer it is "Mezonot". Some hold that since we eat the wafer for the chocolate and the wafer is just to hold it together, it is always "Shehakol" while others argue that the wafer also tastes good (sometimes) and therefore the rule that "Mezonot" is dominant even when it is not the majority should apply.