WD Hitches & Shocks -- Tire Failure Contributors ?

I woke up from a deep sleep with my head spinning with thoughts, feelings, and more questions about marathon tire failures. I wasn't even pondering any of this the night before. Our 2720SL came nicely equipped and we try to be judicious in adding to travel loads. We have an Equalizier 600 lbs hitch that is essential if we are to use our 2001 Tacoma as a TV. The hitch, itself, is physically heavy (80-100 lbs?) but I don't think that its physical weight is as much of an issue as is its weight distribution properties. We load quite a bit of stuff into the bed of the truck and we can see the load compress the springs and lift up the front of the truck. But the WDH remedies this by redistributing the bed load and the tongue weight to the TM's axle and the front axle of the Tacoma. This redistribution would not show up on a GVW scale. I could be wrong but I sense that our setups on our WDH's are putting many of us well over the marathon load limits (especially those of us who are aggressively shifting bed loads). AND --I sense that even with "now level loads" -- our worn, TV shock absorbers are allowing momentary and excessive compressions (from irregularities and dips in the road surface) to be transmitted back to TM's tires and axle -- adding further stresses. Maybe these additional and momentary load blips are factored into the tires' load rating ?? I also wonder if the tire failure rate differs significantly between those folks driving full-sized vehicles WITHOUT WDH's and those driving full-sized vehicles WITH WDH's. We tend to feel that we're in pretty good shape if we stay under gross vehicle weight limits and if we've done a nice job in leveling our loads -- but do you think that our WDH setups (especially as we aggressively level loads) and worn, TV shocks might be real contributors to the tire failure rate? I wish I had a TV that didn't need the assistance of a WDH. Inquiring minds want to know.