Hi, I am struggling by myself to concrete in some wooden fence posts (not ideal I know) for various reasons I am having to find novel ways of supporting the posts when I work and have decided to try and sort of jam the posts in with some shingle when I get the other posts/panels in line (the existing fence is all over the shop, so no easy line to follow...) ANYWAY....my question is; is it possible to mix the concrete up very thin mixture (lots of water) so that it will drain through the shingle and go off like that, rather than just pour it in dry (like it says on the packet) and risk having it just sit on top of the shingle...know what I mean? Any help/advice would me much appreciated! Thanks