Going to a 16" rim/tire set up might give you 1" more in height overall
Adding an LCI Correct Track alignment kit results in roughly 2" increase in height
Need more then that.........flipping axles if spring pack are currently UNDER the trailer axles----gain 3" in height
Spring pack on top of axle or need more then sub-frame is the only way to achieve that.
So how much more height EXACTLY do you need to tow level?
Have you already made adjustments to hitch & pin box?
Lower hitch/raise pin box and still have bed rail clearance??