My business is expanding and I find my old trailer is not up to the task. I am going to build a 6x16 trailer and know what the structural requirements are as well as how to weld. My question is will one axle be sufficient to prevent the trailer from swaying assuming it is mounted correctly. Several people have told me a single axle will sway on the interstate, yet I have seen several 16-20 foot trailers with single axles. I will be towing two commercial zero turn mowers and associated equipment and would prefer not to have my trailer pass me on the interstate. I am planning on using at least 5000 lb axle if I go with single axle or two 3500 lb axles if I go with dual axles. Does this sound ok?