It indeeds shoots up from the deck - two pvc pipes are embedded into the floor and have about inch-sized openings. They're really well hidden even though they're visible the entire second act.
Regarding the actual blood, it never shoots exactly the same, but they definitely tweaked it between St. Ann's and Bway, because Rebecca's face now gets covered in blood. Patrick usually gets the least, but his suit is also brown and harder to tell.