Is it redundant to include 'unique' in this expression if I'm discussing the irregularities of surfers' waves?
Unique simply means one of a kind, exclusive, singular. As such it is improper, though often done, to use it to mean rare or uncommon. Rather like being a little pregnant it cannot be shaded or modified.
If you would like to use "unique" to describe a nuance then it better be one of a kind. I think nuance has its own shadings. In fact it seems you are mixing descriptions that would be more clear if left apart.