Around here they put 2x2 stakes 1 inch below the finished surface of the concrete. The stakes are in a row about in the middle of the pour. On top of the stakes you place a piece of 3/4 inch pipe. You do your screeding on top of the pipe. Drag the pipe with you as you go and there isn't much of a scare to heal before floating. Usually you can just throw a bit of mix back that way and the floating will patch it. It'll take two nails in the top on the stakes to keep the pipe from rolling off, but they just need to stick out of the stakes a 1/2 inch or so. Not enough so they would need to be removed.