lastbit in terms of what your doing you might want to try this as modding not uploaded all details yet but this s on a batch 2 unit and working out the layout for batch 3 will have details on my website when I get around to it.
Thanks crazyearner. Indeed something along the lines of what you did. But batch#3 id different, each 2 modules are arranged in mirror with heatsinks facing one another. And I'd like to keep high airflow on the pcb and chips surfaces too because I believe it may play an important part in cooling.