You may as well get a weigh & retention slings rather than just a wiegh sling smufter.
I completely agree with the earlier post that using your net is poor fish care & shouldn't be encouraged.
I use this one mate
http://www.ebay.co.uk/itm/Sonik-SKS-Weigh-Sling-With-Rods-Support-Bars-Carp-Fishing-Sling-SKSWSWR-/252192472847?hash=item3ab7d7bf0f:g:uvkAAOSwAKxWXEgJ
Great bit of kit and takes seconds to put together/snap down and put it back in the bag.