I'm down to the last part of of the backyard project, extending the pool deck. We had an enormous amount of flagstone left over from both the original flagstone as well as it's replacement stone, don't ask, and decided to use it as part of the deck. The plan is to lay 2 1/2 inches of regular concrete, let it set up a little, and then place the flagstone pieces in individually and use the white cement to fill in the gaps. We want to do it this way for two reasons, first I hate to throw away anything I've paid for without using it, second the white cement looks better but is also far more expensive. So my question is, how much sand do I mix with the white concrete to thicken it up. Should I let it dry a little before trying to work with it? Should I just mix a little at a time or use the concrete mixer and mix a whole big batch? As usual thanks in advance for any advice.