Misconception about what Alclad needs to be sprayed over.

In general, the Chrome, Polished Aluminum, Polished Brass and Stainless Steel should be painted over a gloss black base. However, if you search on Youtube for Model Car Magazine, he has a video there where he is spraying it over grey primer, that he polished out, and the chrome is coming out just as good as I have seen it sprayed over gloss black.

Personally, I think that if a gloss black base is all you need, why go to the trouble of spraying grey primer, and then polishing it to a high shine? Seems like more work then needs to be....ie: work smarter not harder.

As far as how much to use, could be something as simple as what air pressure they were using vs what you were using. Alclad is super thin like water, and needs very little air pressure to spray well, and could be the difference. Plus, the colors I mentioned above you don't really want to put them on thick anyway, as you loose the luster effect that you are using the paint in the first place for. For the chrome, a couple of very light passes is usually all that is needed.

I think that if you applied it properly with the right air pressure, even a larger kit like say the Tamiya 1/32 P-51D probably wouldn't go through a whole bottle of Aluminum for a base color.