They ALL wobble it can be from very slight (leading some owners to believe their's don't wobble) to severe (rare), it is present in any mustation with the spider gene, it cannot be bred out.
Wobble can be slight and become more severe and vice versa, slight wobbler have and can produced severe wobblers and vice versa.
Temperture and stress can affect wobbling as well.
In the vast majority of cases it is mild to moderate and does not affect their life at all.
Bottome line Spiders are not for everyone, do your research, know what to expect and decide whether or not this is something you wish to work with.
I have never let this deter me from working with Spider.