Getting some apparent oddities with the wheel-truing process on a kid's bike. It has 18" wheels, really inexpensive department-store stuff. The rim braking surfaces flare outwards, like \_/, and aren't parallel like most wheels, |_|. The spoke pattern seems normal to me. I have successfully trued other wheels before in hobbyist-style, flipping the bikes over and using brake pads as a guide. I don't have a truing stand yet.

The main issue is, it seems like tightening or loosening one spoke causes major changes elsewhere. I know that adjusting spoke tightness can cause minor reshaping of the rim outside the immediate area, but this is beyond what I'm used to. I feel like a cat chasing its tail, trying to get one part straight and suddenly another part looks bent!

The weird thing is that while I was eventually able to get the left side of the \_/ rim in not-too-terrible condition, the right side still looks a lot more wobbly! Is that normal for this rim shape? Am I just going crazy? Any particular tips or things to keep in mind?