This is the address you've been looking for. I've experimented quite a bit with concrete cause i'm putting con. counters in my apartment kitchen. The best that i've found is adding extra portland cement to a readymix and using a magnesium trowel. I've been using grout to color my experimental counters. Just experiment, that's the best way to go about it. I've been able to get some really smooth pieces although i've yet to tackle the 9' long section!