MTFU, dude Those are really tall tanks. I'm planning to undouble the hp120s for use as single tanks as soon as I can rebuild the valves on the 104s.
well i've lifted those 120 enough times - then i got smart But they are no problems just long tanks for the vertically challanged to lift up into the truck. No troupble really. Where they sit as singles is a function of where you rig them. they are exactly the same tank (valve and all) when done as singles or doubles. the manifold knob extends the length when doubled up but otherwise the same.
They are too long for me - but i would dive them anyway if that was my only option.