The heat riser is a very simple thing. Perhaps the easiest and hardy heat risers you can make has been dubbed a 5 minute riser.
5 minute riser
Your pictures are a bit confusing that stray away from the basic outline a typical J tube RMH generally follows with complexities that may not work very well.
Have you seen a copy of The Rocket Mass Heaters Builders Guide or Rocket Mass Heaters Superefficient Woodstoves YOU Can Build ?
In them, they give brick layouts for J tubes and go into much depth into how to build them. They can answer all sorts of questions and get you going with proven designs that work.