I wanted to move the outboard mount to the starboard side, because that's the side I normally pull the dinghy up on and because I wanted to get it out of the way of the Aries vane. It used to disturb the air over the vane when I was going upwind on a starboard tack.
The arrangement looks a bit cumbersome - I had to add an extra rail, and make quite a large panel to provide lots of places to put u-bolts.
It's a little more 'shoogly' than the stern rail position, but the lashing sorts that out. I may come up with a tidier arrangement ...