If the bolts and nuts are OEM, the nut is held in with a retainer, so it won't fall off. If it has been pieced together, who knows what might be back there. It's hard to tell from your picture, but it looks like you were able to lower the entire spring. Perhaps more in the front than the rear. There should be quite a bit of "every direction" adjustment there, you just need to find the right amount.

Your hinges look plenty rusty, I'd add some oil and work it up and down a bunch. That might free things up by itself. If the tops of the hinges are at different levels from side to side, that may be OK depending on fender placement. You have to work all directions and each side to get the best alignment.

I think after playing with them a bit, you will get a feel for what needs to move where to get the desired result.

Good luck.