Not to derail the brass-fest going on here but aluminum is fine.

You've got a heavy build already, it makes perfect sense to go with brass. Slightly better material etc.

But I've ridden many many bikes with aluminum nips, most of the wheels were built by a barely competent garage mechanic (me) and it's never been an issue. I don't buy most of these arguments if you occasionally clean your bike and store it indoors.

I've you live totally seaside, I could see your point (my scooter rusted in half when I lived in Bermuda). Still though, a tiny bit of care alleviates these problems.