Since you are pretty much starting from scratch again, make the tongue adjustable. Weld a 12 to 18 inch section of 2 inch receiver to the existing tongue structure. Weld your lunette ring to a 2 inch hitch bar and drill the two parts so that you can slide them in or out as needed for the load and terrain.
A couple of 1/2 inch bolts with self locking nuts is adequate to hold the bar in position.
Attach the safety chains to the sliding bar, not the trailer. You will have to extend the lighting harness and loop the excess cable when the bar is retracted.
This setup lets you remove the tongue for storage, since I believe you indicated that garage space is an issue.
Ya that trailer is _seriously_ tongue heavy. I don't see how you can balance it with anything in back, since the weight will more or less be right over the axle. You would have to extend the platform back a couple of feet at least - was that what you had in mind?
Water ballast is fine, until you use it all up at the campsite and then have to tow an imbalanced trailer back home with no ballast. It's better to design in some permanent ballast, like a big house battery or generator. With the trailer you have now, I don't see a satisfactory solution.
Where are your fenders? Those little rain hats don't qualify. Even if the local DOT lets you get away with open tires, you should, for the sake of cars following you on the highway, put on some real fenders and mudflaps. If I were behind your trailer when it flipped a rock into my windshield, I would be _seriously_ ticked off. In WA the fenders/ mudflaps are "supposed to" extend to the axle centerline or below - it isn't enforced in any way but it is a good rule of thumb.
I'm not trying to be a hard @ass - but you should be aware that those dinky fenderettes will get you into trouble one day. My trailer doesn't throw rocks.....:
John Davies
Spokane WA