The weight range of 7000lbs is the maximum towing capacity the frame,chassis is rated for along with the 700 tongue weight. You're doing it right with teh numbers you have as far too many people think they can tow what the vehicle is rated for and realize that the vehicle MAY be capable of towing it, but that doesn't mean you SHOULD.
My E1 is a work in progress and is currently 2450 empty with a GVWR of 3500. I've done a few mods that have increased the weight and a few mods that have saved weight. The hitch is at 350lbs, but I haven't checked it yet with the KTM 500 on the front deck. Will be interesting to see how not having any water in the tank and a KTM on the deck turns out.
When I get the chance I will be putting scales under each wheel and tongue and doing an Excel Weight & Balance program for the E1 to move things around and make changes to determine the effects of the tongue weight.
My tow vehicle is rated at 7500lbs witha tingue of 700 of which I don't go near that for power/transmission and safety reasons.
Hope that helped.
I'll post more pictures as I get them.