I remember well how excited I was when I could get brass and Viton needles, and how they would solve problems I didn't know I had. Long time ago.
Now I'm going the other way, I save every single nylon float needle I can find and retrofit them. I used to have all kinds of issues with my 72 Trident, slow tickling, long warm-up, inconsistent idling and persistent float bowl leaks. After I changed back to nylon, all these issues simply went away.
To recommission nylon needles I use chrome polish on a piece of cloth, and I clean the float seats too with polish on a Q-tip.
Aluminium needles may be great for what I know, but as long as I can find nylon ones I'll fit those.
I might add that I use chrome polish to clean needles and seats on modern carbs as well, and it works even on Viton.