Look up the dry weight of your fiver, then take it as loaded for travel to a scale and do a two trip weigh.
1st connected all axles TV front and rear fiver pair. Then drop the fiver and re-weigh the TV front and rear. Then add together the TV axles loaded and unloaded, the difference is the fiver PIN weight.
Now add the pin and fiver axle weights to get the fiver total weight loaded, THEN subtract the DRY weight from the Loaded weight, that is the weight of your STUFF!!! It should actually a bit high as most stated dry weights are a bit low.