I'm getting some conflicting advice on the best mix to use for setting fence posts for a 6ft vinyl privacy fence. I've been told that any Quikrete mix (like the #1101) will set up if poured dry. I've also been told that the fast setting the fast setting #1004 is far better. Someone even told me that the non-fast setting will only have half the strength of the red bag, fast setting mix if poured dry. I'd like to save some money if possible but don't want to sacrifice strength over the years as this fence will catch lots of wind over the years.