I had a 2010 Outback and ditched the Hobie cart in favor of the C-tug as it was a PITA to turn the Outback on the side to insert the cart.
I found the best location for the C-tug was under the front part/location, of the seat and I ran the straps between the side carrying handles located alongside/inside the hull.
Unless C-tug has improved the original strap-buckle design, I replaced the factory straps with a 1 1/2" wide NRS tie down strap.....it has a cam locking mechanism that is bullet proof and will not slip.
See
http://www.kayakshed.com/nrs/1-5-wide-straps The C-tug held my Outback and was well balanced......just open up the pads as wide as they will go....place the cart next to the Outback and lift/lay the Outback on to the C-tug.....align and insert straps under the inside cockpit carrying handles, pull to tighten the straps....ready to go.