There are shims that go behind the spindle that can correct camber.
There are offset balljoint bushings that can correct camber and caster.
They have limitations.
Also should look at SAI (kingpin inclination) numbers. That is like caster in you draw a line through the upper and lower ball joints, but it is in the camber direction. Depending on if the variation is corrected inside or outside the balljoint will change the SAI.
As for bending the axle to get the numbers, it may be the right way to do it at times and the wrong way at others. Depends on where the error is at. I feel the axle tubes are rarely as straight as they should be, so tweaking the housing to fix stuff can be a good thing. But if the knuckle itself is tweaked bending the housing to fix that is just making more problems. Figuring out where the error is really occurring at can be the hardest part. That is where the SAI numbers help point the way.