as pointed out dry hitch weight is usually way under real hitch weight. The dry hitch weight on my trailer was in the low 700lb range. Real hitch weight with batteries, propane, water and all the stuff in trailer is 1450lbs.
your 600lbs dry could easily top 1000lbs. figure it will go up by the weight of each battery (70lbs each) and 60 lbs for two 30lb full propane tanks. That's 200lbs right off the bat. Stuff on the tongue adds virtually lb for lb. stuff in the pass through close to that.
And remember a WD hitch does NOT change tongue weight!!!! It just distributes weight from the rear axle of the TV to the TV front axle and trailer axles.