I've also done quite a few different brackets - including ladder bars and a new spring cup/mount on a Ford 9" in my pickup. I did the same thing with a 4-bar on my A-bone. Never trued either, and never had a bearing failure. However, I used the same technique - moving from side to side in a cris-cross pattern. Doesn't make it right, but it worked.

I've seen recommendations for removing everything, then putting a steel bar jig through the axle tubes to hold them true. I've never believed that would work. If you heat the tube unevenly, it will still try to warp, but instead of moving, it will go under tension. It won't move until you remove the jig. Of course, it's been a long time since my mechanics of materials course, so I could be wrong.