That's a sweet looking stand and tank. Great job!
As you have already stated i would add some more bracing to the back and sides. I know you dont want to come home to a dining room swimming pool.
add some more bracing, and put foam between the tank and the stand to make up for it being unlevel (depending on how unlevel it is, you might want to fix it).
The last thing you want to do is trash that beast.
You can use the foam that they use as insulation from any hardware store. I got some stuff that a guy had laying around that they use to pack bombs with ( i dont want to know how he got it).
Just ask for the stuff that goes under vinyl siding. Depending on how big your gap is, you might want to go pretty thick with it.
I would fill that end gap or the uneven part with either wood filler, wedge and fill some shims or start over and correct the problem. Tahnks for hearing me out.![]()