Based on this, I would say that I am hopelessly nomothetic in temperament.

Though I do try to temper it.
If I grasp the distinction correctly, a historian like Eric Hobsbawm would be more on the nomothetic side, while Howard Zinn would be more idiographic. What would be an example of a good mix of nomotethic and idiographic? Braudel's
longue durée, mayhaps?
Yes I think
longue durée is a good example - it seems to capture the essential interplay between the surface-level idiographic factors and deeper nomothetic laws, addining up to an expression of 'dynamism' which makes sense.
In metaphysical terms, though, the essential distinction comes down to how you conceive of determinism.
A 'hard determinist' would say that, necessarily,
all processes are nomothetic. There is
only the nomothetic, because everything is the result of one law or another.
However, I think in this hard determinist conception, the case for an appreciation of the idiographic is even more strongly made, since there will be circumstances arising from the interaction between various nomothetic processes which will only
ever happen once in the entire history of the universe (saving certain ideas of infinity of course). That is, even if everything is the outcome of an interaction between universal laws, many of these interactions are so unlikely that they can be hueristically treated as unique; that is, properly idiographic.
In terms of human personality, we must allow ourselves to be struck by the utter complexity of social forces acting upon the individual, and therefore consider just how 'idiographic' individual human personalities are.
Now, that is not to say that there is no such thing as universal human nature, merely that we should consider if the nomothetic factors are not merely overstated.
We're in the realms of thought-experiment here, but there is a case to be made that the
vast majority of human behaviour is essentially an idiographic result of culture.
I'll give you an example. Take game theory and how it is used by economists and others to build fairly effective models of human behaviour. At base, the nomothetic axiom is very small here - it assumes that human beings are rational actors.
Now if we can extrapolate
so much about behaviour based upon a simple axiom like this, then that necessarily shifts the causal burden much more heavily towards environmental idiographic/cultural factors in determining how human beings behave.
For instance, we could say that the technological environments of each historical era are much more causally responsible for human behaviour than any essential notions of 'universal human nature', because such behaviours are predicted by a very small number of simple axioms (e.g. Game theoretic rationality, &c.).
I'm playing devil's advocate here again, but nonetheless the change in perspective allows for a fuller appreciation of the power of idiographic factors.