I actually did play my 'Hero' 8 bass PA upside down for a while when learning. I can still do it a bit, but the larger teh box, the more difficult - and you would need to swap the straps around for comfort - on a tiny box, the straps are mainly to stop anyone racing up to you and grabbing the box away from you.... :-)

I have found that 'swapping hands' when learning a physical motor skill often helps me progress much faster at that initial stage of 'motor frustration' - when you know what the hands should be doing, but it just isn't working. I have a mild degree of MMD in hnads and arms since birth, so don't know whether it is a trick that works for me, or it would assist everybody, but suspect it might... My grandad was ambidextrous, and I have found that I can be at times. I have found that I have to mentally 'mirror' what I was doing right handed, then when I go back to right hand, I mentally mirror again. Perhaps it is the focussed concentration that assists.