Trailers make a lot of sense when you need to carry a lot of gear, it is better than overloading the bike. Single wheel trailers look nice but everyone I know who has gone down the trailer route says two wheeled trailers are better.
I found some fitting instructions for the SW Motech stand HERE it looks like the spring attaches higher up on the actual stand than on the one you have, it says there is an original spring hanger on the frame already.