Can anyone tell me if the state usually holds powerful testimony or events until the end of trial as this is the first I've covered?
Depends on how the State is stating their case. In this instance they clearly defined in their OS that they are going day-by-day through the timeline, and the witnesses will be called according to that schedule.
Since the meat of this matter will be based on forensic experts, then, yes, in this case, the powerful testimony will be towards the end.