Wheeleez cart and Hobie hull -- Scupper cart blowout

I had a major blowout coming down the 'hill' at HMB last weekend -- My ol' (seriously, ancient) scupper cart buckled on a flat tire and put me in a bind. Thought I'd give the Wheeleez top loading cart a try so that I could position the wheels more towards center and transport my fully loaded rig easier. Unfortunately, the cart frame doesn't fit the hull of my Compass Duo very well. It presses on the pontoons, and with the kayak fully loaded with gear I'm certain the pontoons would be bent/flexed around the frame of the cart. I think the top loading cart has serious advantages over the Hobie Trax plug-in cart (the main advantage for me being landing and not having to unload all my gear to plug in the wheels), but the stress on the pontoons from the cart frame might be a deal breaker. Before I throw in the towel on the top loading cart, anyone have a fix?

Here's what I did...  3" PVC pipes attached 10.5" apart to the top of the cart.  I have since put beach wheels on the cart and with two straps, it doesnt get much more secure.  That said, its bulky, heavy, and not great for strapping to the back of the yak to take with you on the water. 

Sea tug.