I was told that I should not allow the tongue weight to reach more than 1,000 lbs. by the converter. Using the scale with the trailer loaded as I normally load it I pegged the scale at over 2,000 lbs. This was with both vehicles pointed forward centered over the axles of the trailer plus a golf cart in the front. I blew a front trailer tire which made me think that there could be a possible heat problem due to the weight. I would highly recommend scaling the tongue and adjusting the load accordingly. I have a winch in my trailer and it was no problem to winch the bottom car in backwards.
When I had the blow out I changed all of my tires out to a Michelin that allowed a higher load plus allowed a maximum 110 psi air pressure. Before you do this you need to be sure your rim will accept this much psi. Fortunately, the Alcoa rims on my trailer would accept this.
My mileage on my H has always sucked. It a 2006 model that I had built new. It now has 45,000 lbs. Hopefully, as it gets broken in it will improve. Detroit say they will not look at this until I have at least 70-80,000 miles on it.
Hope this helps