I have a Corbra Tandem ( We are a choosen few, the best usually are....
) have fished it for 14 years, also I have made a PVC cart which the yak sits on and not thru the scuppers, Where the 1" PVC joins at elbows I used removable "D" Pins and drilled them thru the elbows I used 1/4" pins.(Prevents the PVC from twisting) and added 30cm Wheeleze, It all breaks down and can store inside the Cobra Tandem,
I have some old roofpads from surfing used to rest the kayak on ( I never had any issue with the hull flexing on the pads), and I also used a ( 1 ) roof strap from my surfboards also to attach to yak, its shorter and works great. Its perfect size. I take some pics and post.
The cart works great over any sand , and with all the gear in tow.,
I usually walk the cart back to the truck, but have taken it with me on occasions. I usually like to keep the "trunk" for fish and battery storage.
If you see and old Gray Cobra Tandem in LJ look me up and I'll show ya.