I have bred two totally unrelated animals and got a train wreck of a clutch. Out of 6 eggs, only 2 reached full term. One died in the egg the day before the other hatched. The one that died was missing one eye and had severe spinal deformations. The one that "lived" also had kinks and did not survive after not being able to eat.
Deformities can happen for all sorts of reasons and no amount of outcrossing will minimize or get rid of the spider wobble. It is linked to the gene. (or so many speculate). All spiders wobble. They are one of the most outcrossed mutations due to the fact they have no super form.
Now you may get to the point if you are line breeding that after many many generations you start to see problems, but within only a few, I doubt you'll see many issues, and most of the time, breeders are not going to continually line breed unless they have a new mutation they are trying to develop, and even then they only do it for a few generations.
