Well..... had some very enjoyable dives using the deco sidemount over one of my homemade minimalist harnesses. Tested it out with 2, 3 and then 4 cylinders (2x AL80 and 2x AL40) for technical diving and it functions excellently so far.
The next step will be to add a 2nd bladder, sandwiched to the primary) for redundant buoyancy..... easy, as it'll use the same mounting bungees.
Pics to follow...
Andy, do you have pictures of how does it look out of the water from the front and rear with the tanks on ?